Chem 1 EXAM
Determine the mass in grams of 6.03 × 10²¹ atoms of arsenic. (The mass of one mole of arsenic is 74.92 g.)
(6.03 x 10^21)(74.92) / 6.022 x10^23 =0.750g
convert 0.0134 L to milimiters
0.0134 L x 1000mL/1L = 13.4 mL
A patient is required to taken an IV drug for cancer treatment. The required dosage is 5.0 mg drug per lb patient body weight every day. Each of the bags of the drug contains 250 mg drug. If you are treating a 150 lb patient, how many bags of the drugs are needed each day?
150 lb patient x 5.0 mg drug/1lbpatient x 1 bags/250 mg drug = 3.0 bags
a person loses 2.70 lb in two weeks. how many grams did they loose?
2.70 lb x 453.6g/1lb = 1220g
convert 2.87 kg to grams
2.87 kg x 1000g/1 kg = 2870 g
A chemist is trying to identify an unknown metal, and finds that 25.0 cm³ of the substance has a mass of 224.43 g at 20°C. Which of the following metals is it?
224.43g/25.0cm3 = 8.98gcm3
How many moles of calcium atoms do you have if you have 6.54 × 10²¹ atoms of calcium. (The mass of one mole of calcium is 40.08 g.) Answer: 0.01086 mol
3.00x10^21 atomsofCa x 1molCa/6.22x10^23 atomsofCa = 0.00498 mol Ca
Which of the following would be considered a quantitative observation?
3.2 g of sulfer was formed
Which of the following quantities is equivalent to 3.7 cm?
3.7 cm x 0.01m/1cm x 1km/1000m = 3.7 x10^-5 km
Determine the number of atoms in 33.0 grams of bromine, Br. (The mass of one mole of bromine is 79.90 g.) Answer: 2.49 x10^23
31. 0 g Br x 1mol Br/79.90 g Br x 6.022x10^23 atoms Br/1mol Br = 2.34 x10^23
convert 8.93 mililiters to microliters answer: 8.93 x10^3 uL
5.01 mL x 1L/1000mL x 1x10^6 uL/1L = 5.01 x10^3 uL
convert 5.32 x 10^-7 s to microseconds
5.32x10^-7 s x 10^6 us/1s = 0.532 us
You were given a dose of 500 mg rather than 500 μg of a drug. How much more of the drug did you receive?
500 mg x 1000ug/1mg =500,000 500,000 ug/ 500 ug = 1,000 times
convert 677 nanograms to miligrams 6.77 x10^-4 mg
501 ng x 1g/1x10^9ng x 1000mg/1g = 5.01 x10^-4 mg
a large stone weighs 53.0 kg. how many pounds does it weigh
53.0 kg x 2.205lb/1kg = 117 lb
which of the following quantities is equivalent to 594 mg?
594 mg x 1g/1000 mg = 0.594 mg
Determine the number of atoms in 73.0 grams of calcium, Ca. (The mass of one mole of calcium is 40.08 g.) Answer: 1.10 x10^24
61.0 g Ca x 1molCa/40.08gCa x 6.022x10^23 atoms Ca/1molCa = 9.17 x10^23
convert 7.54 x 10^-8 m to nanometers
7.54 x 10^-8 x 10^9nm/1m = 75.4 nm
Determine the mass in grams of 8.84 × 10²¹ atoms of carbon. (The mass of one mole of carbon is 12.01 g.) Answer: 0/176 g
7.75 x 10^21 atoms of c x 1 mol C/6.022 x 10^23 atoms of C x 12.01g C/1 mol C =0.155 gC
Glucose is an example of a
A compound has two or more elements chemically bound together and cannot be separated by physical means.
Aluminum
Al
The number 6.040 has ___ significant figures.
All non-zero digits, zeros found between two significant digits, and zeros following a significant digit in a decimal are considered significant. Leading zeros and trailing zeros without a decimal point are not significant. So in the number 6.040, all of the digits are significant resulting in four significant figures.
The number 0.0509 has ___ significant figures
All non-zero digits, zeros found between two significant digits, and zeros following a significant digit in a decimal are considered significant. Leading zeros and trailing zeros without a decimal point are not significant. So in this number, only the underlined digits are significant resulting in three significant figures.
Which one of the following is an example of an element? Answer: Iron
An element has only one type of atom present. Elements can be found in the Periodic Table.
Which one of the following is an example of an element? Answer: nickel
An element has only one type of atom present. Elements can be found in the Periodic Table.
What is the correct IUPAC name for BaI₂?
Barium Iodide
Which of the following does NOT describe the element bromine (Br)?
Bromine (Br) is in group 7A (17), which are collectively called halogens.
Cd
Cadmium
How many electrons are in a neutral ⁴¹Ca atom?
Calcium has 20 protons. Therefore a neutral calcium atom has 20 electrons.
What is the correct IUPAC name for Ca(NO₃)₂?
Calcium nitrate
Cathode rays are composed of what fundamental particle?
Cathode rays are composed of electrons.
What is the correct IUPAC name for CoCl₂ ?
Cobalt(II) chloride
What is the correct IUPAC name for CoPO₄?
Cobalt(III) Phosphate
Which of the following numbers contains three significant figures?
Count the number of significant figures in each option. Be sure to account for non-zero digits, zeros found between two significant digits, and zeros following a significant digit in a decimal. Leading zeros and trailing zeros without a decimal point are not significant. Choice C, 0.00230, contains three significant figures.
Which of the following numbers contains five significant figures?
Count the number of significant figures in each option. Be sure to account for non-zero digits, zeros found between two significant digits, and zeros following a significant digit in a decimal. Leading zeros, and trailing zeros without a decimal point, are not significant. Choice A, 50.260, contains five significant figures.
A student is determining the density of an unknown metal with a mass of 32.56 g. The student partially fills a graduated cylinder with water and measures the volume of the water by itself as 14.78 mL. The student then adds the metal to the water and measures the new volume as 20.44 mL. What is the identity of the metal?
Density is a mass divided by a volume. You have been given the mass of 32.56 g. To find the volume of the metal, you need to determine the difference in volume between the water by itself and the water with the metal: 20.44mL−14.78mL=5.66mL and then density can be calculated: massvolume=32.56g/5.66mL = 5.75gmL The density of 5.75 g/mL corresponds with the metal tin.
Ignoring the sign, which has a greater magnitude of charge?
Electrons and protons have opposite charges that are equal in magnitude. They have equal charges
Elements that are most similar in their properties are found _____
Elements that are in the same group have similar properties.
Which scientist developed the nuclear model of the atom?
Ernest Rutherford developed the nuclear model of the atom.
Group 18 elements were called the noble gases originally because
Group 18 elements were called the noble gases originally because they were believed to be 'too noble' to react with other elements.
Which of the following are physical properties of matter?
If a property (density) can be measured without changing the substance, it's a physical property.
Which one of the following is an example of a heterogeneous mixture?
If a sample of matter is a mixture that is not uniform in composition, it's a heterogeneous mixture. Italian salad dressing does not have a uniform composition. italian salad dressing
Neutral atoms of all isotopes of a given element have the same
Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons and electrons.
An atom of the isotope ¹³³Cs contains how many protons (p), neutrons (n), and electrons (e)? Answer: 55 p, 78 n, 55 e
Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons. The standard notation for an isotope is to indicate the mass number because its protons and electrons do not change. massnumber ^ element The symbol 133Cs indicates that the mass number is 133. Cesium has an atomic number of 55, indicating it has 55 protons, and 55 electrons in the neutral atom. The mass number of an atom is representative of the number of protons and neutrons. Calculate the number of neutrons from the mass number and the number of protons. 133=55+x 78=x
Potassium
K
Hg
Mercury
Manganese
Mn
Which subatomic particle is found in the nucleus and has no charge?
Neutrons are subatomic particles found in the nucleus that have no charge.
the element symbol for nickel is
Ni
The density of water is approximately 1 g/cm³. Which of these objects will float on water?
Objects that have a density of less than 1gcm31gcm3 will float on water. Objects that have a density of greater than 1gcm31gcm3 will sink in water. So the cedar wood block, d = 0.380 g/cm³ will float.
Which of the following contains the highest number of atoms?
One mole of any substance is equal to 6.022×1023 particles of that substance.
Which subatomic particle is found in the nucleus and has a positive charge?
Protons are subatomic particles found in the nucleus that have a positive charge.
What is the correct IUPAC name for SrCl₂?
Strontium chloride
How many protons are in an atom of strontium-90?
Strontium has an atomic number of 38. The atomic number is the number of protons in an atom.
The element symbol for arsenic is _____
The Periodic Table provides element names and symbols. The element symbol for arsenic is "As".
What does the mass number of an atom represent?
The mass number of an atom represents the total number of protons and neutrons in the atom.
How many neutrons are in a ⁴He atom?
The mass number, 4, is the number of protons plus neutrons. Because helium always has 2 protons, this atom has 2 neutrons.
How many significant figures does the number 48.050 have?
There are 5 significant figures in 48.050. Count the number of significant figures. Non-zero digits, zeros found between two significant digits, and zeros following a significant digit in a decimal are significant. Leading zeros and trailing zeros without a decimal point are not significant. The trailing zero in this case is significant because it follows a significant digit in a decimal.
What is the correct IUPAC name for AlBr₃?
aluminum bromide
What is the correct IUPAC name for Al(NO₂)₃?
aluminum nitrite
What is the correct IUPAC name for CuSO₃?
copper 2 sulfite
Density is defined as mass _____________ volume.
divided by
F
fluorine
What is the correct IUPAC name for FeCl₃?
iron 3 chloride
What is the correct IUPAC name for Li₃PO₄?
lithium phosphate
What is the correct IUPAC name for MgO?
magnesium oxide
what is the correct IUPAC name for KF?
potassium floride
What is the mass number of platinum-198? Answer: 198
.Isotopes can be written as "element-mass number". For example, "platinum-194" indicates an atom of platinum with a mass number of 194.
How many protons are in an atom of Zn? Answer: 30
.The atomic number represents the number of protons in an atom. For example, consult the periodic table for cobalt. It has an atomic number of 27, indicating it has 27 protons.
What is the mass number for an atom of calcium containing 20 protons and 22 neutrons? Answer: 42
.The mass number of an atom is representative of the number of protons and neutrons. The number of protons can be found from the atomic number of the element on the periodic table. Calculate the mass number using the given number of protons and neutrons. For example, if there are 20 protons and 25 neutrons, the mass number can be calculated like this: 20+25=4520+25=45.
Determine the mass, in grams, of 0.410 moles of S (1 mol of S has a mass of 32.07 g). Answer: 13.1 g
0.350 mol S x 32.07 g S/1 mol S = 11.2 g S
convert 0.386 g to milligrams. use only to metric sysmtem
0.386 g x 1000mg/1g = 386 mg
Determine the mass, in grams, of 0.395 moles of Pb (1 mol of Pb has a mass of 207.2 g). Answer: 81. 8 g
0.400 mol Pb x 207.20 g Pb/1 mol Pb = 82.9 g Pb
Determine the mass, in grams, of 0.230 moles of Mn (1 mol of Mn has a mass of 54.94 g). Answer: 12.6 g
0.450 mol Mn x 54.94 g Mn/1mol Mn = 24.7 Mn
Determine the mass, in grams, of 0.245 moles of Co (1 mol of Co has a mass of 58.93 g). Answer: 14.4 g
0.550 mol Co X 58.93 gCo/1 mol Co = 32.4 g Co
Determine the mass, in grams, of 0.670 moles of I (1 mol of I has a mass of 126.90 g). Answer: 85.0 g
0.650 mol I X 126.90 g I/1 mol I = 82.5 g I
Determine the mass, in grams, of 0.565 moles of Si (1 mol of Si has a mass of 28.09 g). Answer: 15.9 g
0.750 mol Si x 28.09 g Si/1 mol Si = 21.1 g Si
Which one of the following is the longest length? 840 m
1) 840 m 2) 0.084 km x 1000m/1km = 84 m 3) 8.4x10^9nm x 1m/1x10^9 nm = 8.4 m 4). 8.4x10^7 um x 1m/1x10^6um = 84 m
Human blood typically contains 1.04 kg/L of platelets. A 1.23 pints of blood would contain what mass (in grams) of platelets? (1 gallon = 3.785 L, 1 gallon = 8 pints). answer: 605 g
1.01 pints x 1gal/8pints x 3.785L/1gal x 1.04kg/L x 1000g/1kg = 497 g
How many atoms are in 4.2 mol of carbon? Answer: 2.5 x10^24
1.2 mol C x 6.022x10^23 atoms/1molC = 7.2 x 10^23 atoms of C
How many atoms of vanadium are in 1.28 grams of vanadium?
1.28 gV x 1molV/50.94 gV x 6.022x10^23 atomsV/1 mol V = 1.51 x10^22 atoms V
convert 2.3 hours to seconds
2.3 hr x 3600s/1hr =8280 s
A chemist has a block of copper metal (density is 8.96 g/mL). The block weighs 2.3. What is the volume of the aluminum block in mL? Answer: 0.257 mL
2.3/8.96 gmL = 0.257 mL
A chemist encounters an unknown metal. They drop the metal into a graduated cylinder containing water, and find the volume change is 4.1 mL. If the metal weighs 3.5 g, what is the density of the metal? Answer: 0.85 g/mL
2.3g/4.1 mL = 0.56 g/mL
How many moles of iron atoms do you have if you have 7.60 × 10²³ atoms of iron. (The mass of one mole of iron is 55.85 g.) Answer: 1.262 mol
2.50x10^23 atoms of Fe x 1molFe/6.022x10^23 atoms of Fe = 0.415 mol Fe
Which of the following is a chemical change?
A chemical change results in the formation of a new substance with a different composition and properties. A physical change results in a change to the physical properties of a substance but it still remains the same substance with the same composition. Choice A, cooking an egg, is a chemical change.
Which of the following describes a chemical change involving water?
A chemical change would involve the atoms found in a water molecule rearranging to form a new molecule or molecules with different composition(s). A physical change would involve the water molecules changing their state of matter but still remaining water molecules. Choice C describes a chemical change. H20 --> H2 +1/2O2
Which one of the following is an example of a compound? Answer: water
A compound has two or more elements chemically bound together and cannot be separated by physical means.
Which one of the following is NOT an example of a compound?
A compound has two or more elements chemically bound together and cannot be separated by physical means. concrete
How many electrons are in a neutral carbon-14 atom?
A neutral atom has the same number of protons as it does electrons. All carbon atoms have 6 protons. Thus a neutral carbon-14 atom has 6 electrons.
Which two particles of the atom have nearly identical masses?
A proton has a mass of 1.673×10−271.673×10−27 kg, an electron has a mass of 9.109×10−319.109×10−31 kg, and a neutron has a mass of 1.675×10−271.675×10−27 kg.
which has a greater mass? Proton
A proton has a mass of 1.673×10−271.673×10−27 kg, an electron has a mass of 9.109×10−319.109×10−31 kg, and a neutron has a mass of 1.675×10−271.675×10−27 kg.
A homogeneous mixture is also called a ____________.
A solution is a type of homogeneous mixture composed of two or more substances.
Calcium is an example of a(n)
An element has only one type of atom present. Elements can be found in the Periodic Table. element
Gold
Au
What is the value of Avogadro's number?
Avogadro's number is a constant that represents the number of particles in one mole of a substance. There are 6.022×10236.022×1023 particles in one mole.
the element symbol for copper is
Cu
Which will have a higher density: 1.00 g of pure gold or 1.00 kg of pure gold?
Density is an intensive property - it is the same no matter the amount of a given substance you have. It is a ratio of mass to volume, so as mass grows, so will volume at the same rate for a given substance.
Who developed the earliest form of our modern periodic table?
Dmitri Mendeleev developed the earliest form of our modern periodic table.
Which of the following states of matter are considered fluids? I) Solid II) Liquid III) Gas
Fluids flow under pressure. This is a property of both liquids and gases.
Grape Juice is an example of
If a sample of matter is a mixture that is uniform in composition throughout, it's a homogeneous mixture.
Which of the following pairs represent isotopes?
Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons. The standard notation for an isotope is to indicate the mass number because its protons and electrons do not change. massnumber^ element
Italian dressing contains olive oil and vinegar, which will separate out from each other if left to sit. This makes the dressing a:
Italian dressing is a heterogeneous mixture that has a difference in composition within the mixture.
Kelvin is the SI unit for which physical quantity?
Kelvin is the SI unit for temperature. The relationship between degrees Celsius and degrees Kelvin is ∘C=K−273.15.
The number 0.0087 has ___ significant figures.
Leading zeros and trailing zeros without a decimal point are not significant. So in this number, only the digits that are underlined are significant resulting in two significant figures.
Which of the following is an extensive physical property of matter?
Length changes based on how much of a substance is present. It can also be observed through physical means.
What is the name of the SI unit for length?
Length is a measurement of an object from end to end. The metric system is built on the SI unit for length, which is the meter.
Which of the following states of matter is portrayed by the following description: assumes the shape of its container because it has a definite volume but no specific shape?
Liquids expand horizontally to fit the shape of their container, but since they have a fixed volume, they do not fill the container vertically.
A temperature of 103°F or higher is considered a medical emergency. Patient A comes in with a temperature of 38°C. Patient B comes in with a temperature of 313 K. Is either patient having a medical emergency?
Starting with Patient A:°F=9/5×°C+32 °F=9/5×38∘C+32° F=100.∘F° Patient A is not having a medical emergency. Next Patient B. It will involve two temperature conversions.°C=K−273.15° C=313K−273.15° C= 39.85∘C° Next, change the Celsius temperature to Fahrenheit° F=9/5×°C+32 °F=9/5×39.85∘C+32 °F=104∘Patient B is having a medical emergency.
Which of the following temperatures is the coldest?
Temperature in Kelvin (K) is the lowest because it is the absolute temperature. Given the same numerical value, Kelvin would always be the lowest temperature.
Similar properties recur periodically when elements are arranged according to increasing atomic number is the statement of the ______.
The Periodic Law states that similar properties recur periodically when elements are arranged according to increasing atomic number.
Which of the following is an alkaline earth metal?
The alkaline earth metals are found in Group 2 and include Be, Mg, Ca, Sr, Ba, and Ra. Example: Beryllium
An unknown element X has the following isotopes: ²⁵X (80.5% abundant) and ²⁷X (19.5% abundant). What is the average atomic mass in amu of X?
The atomic mass is an average that represents the abundance of each isotope. It can be calculated by multiplying each atomic mass by its abundance in decimal form and adding them together. (0.805×25)+(0.195×27)=25.4
Which of the following is an intensive physical property of a lump of coal?
The color of the coal can be observed through physical means (the naked eye), and does not depend on the amount of coal present.
How do you convert a Celsius temperature to Kelvin?
The formula for converting Celsius to Kelvin is: K = °C + 273.15
Which of the following is a halogen?
The halogens are found in Group 17 and include F, Cl, Br, I, At, and Ts. Example: Iodine
Which of the following is a main group element?
The main group elements are elements that belong to the s and p blocks of the periodic table. Example: Bismuth
What element with a mass number of 100 has 56 neutrons in its nucleus?
The mass number of an atom is representative of the number of protons and neutrons. Calculate the number of protons from the mass number and neutrons. 100=x+56 44=x Then, find the element in the periodic table that contains 44 protons. The number of protons is indicated by the atomic number. The element is Ruthenium (Ru).
What is the mass number for an atom of nickel containing 28 protons and 36 neutrons? Answer: 64
The mass number of an atom is representative of the number of protons and neutrons. The number of protons can be found from the atomic number of the element on the periodic table. Calculate the mass number using the given number of protons and neutrons. For example, if there are 28 protons and 33 neutrons, the mass number can be calculated like this: 28+33=6128+33=61.
What is the atomic number for an element whose mass number is 92, which contains 51 neutrons per atom?
The mass number of an atom is representative of the number of protons and neutrons. The number of protons can be found from the atomic number of the element on the periodic table. Calculate the number of protons/atomic number using the given mass number and neutrons. For example, if an atom has a mass number of 92 and contains 51 neutrons, the number of protons/atomic number can be calculated like this: 92−51=41.
Which of the following is NOT a metalloid?
The metalloids are: B, Si, Ge, As, Sb, Te and Po. Example: Lead
Which one of these represents a CHEMICAL change?
The molecules in sour milk are different than those in fresh milk, so a chemical change has occurred. Also, milk can't "unsour" and that is another indication of a chemical change.
The nucleus of an atom contains:
The nucleus of an atom contains protons and neutrons.
Perform this mathematical operation and express the answer to the correct number of significant figures: 0.085631 × 1.32
The number 0.085631 contains five significant figures and the number 1.32 contains three significant figures. When multiplying numbers, the result is reported with the significant figures of the number with the fewest significant figures. In this case, the result is reported to three significant figures. 0.085631×1.32=0.11303292=0.113
Express the number 554,780,000,040 in scientific notation to three significant figures.
The number 554,780,000,040 contains 11 significant figures. To convert it into scientific notation, the decimal place is moved to the left to create a coefficient that is a number that is less than 10 but greater than 1. In this case, that is 5.54780000040×10^11, but this number has 12 significant figures. Rounding this number to 3 significant figures results in 5.55×10^11
Which of the following metric prefixes corresponds to 10³?
The prefix kilo- indicates 10^3. Common prefixes and their notation are shown in the table.
Which of the following metric prefixes corresponds to 10⁶?
The prefix mega- indicates 10^6. Common prefixes and their notation are shown in the table.
Which of the following metric prefixes corresponds to 10⁻⁶?
The prefix micro- indicates 10^−6. Common prefixes and their notation are shown in the table.
How many milliliters are in a liter?
The prefix milli- indicates 10^−3, so one mL is 0.001 L, and there are 1000 mL in 1 L.
Which of the following metric prefixes corresponds to 10⁻³?
The prefix milli- indicates 10^−3. Common prefixes and their notation are shown in the table.
Which of the following is a physical change?
The process of boiling water is a phase change from liquid to gas and represents a physical change.
Which of the following is a chemical change?
The process of glycolysis converts a molecule of glucose into pyruvic acid and energy for a cell. Because chemical bonds are broken and formed, glycolysis is a chemical change.
According to the gunpowder reaction, which of the following is true?
The same five elements appear on each side of the reaction arrow
Read the thermometer given. What would the temperature be in Kelvin?
The thermometer reads 37.0 °C. Remember that you should estimate the tenths place, since the markings represent the ones place. The formula for converting Celsius to Kelvin is: K = °C + 273.15 K=37.0°C+273.15 K=310.2 K
Read the thermometer given. What would the temperature be in Kelvin?
The thermometer reads 37.0 °C. Remember that you should estimate the tenths place, since the markings represent the ones place. The formula for converting Celsius to Kelvin is: K = 37.0°C + 273.15 K=310.2 K
Which of the following represents the correct conversion factor between grams and pounds? I) 453.6 pounds per gram II) 453.6 grams per pound III)1 gram per 453.6 pounds
There are 453.6 grams in one pound. This conversion factor would then be represented as: 453.6 grams per pound.
To convert from grams to number of molecules, you need to use:
To convert from grams to number of molecules, you must first convert the grams into moles, which requires the molar mass, and then you must convert the moles into number of molecules, which requires Avogadro's number.
Which of the following is a transition metal?
Transition metals are found in the d-block of the periodic table. Example: Silver
How many neutrons are in an atom of uranium-235?
Uranium-235 has a mass of 235. Uranium always has 92 protons. Therefore, uranium-235 has 143 neutrons.
A cylindrical glass tube 20.0 cm in length is filled with acetone. The mass of the acetone to fill the tube is found to be 17.13 g. Calculate the inner diameter of the tube in cm. The density of acetone is 0.784 g/mL. Answer: 1.18 cm
V acetone= 19.33/ 0.784 g/mL = 24.6556 mL x 1cm^3/1mL =24.6556cm^3 V cylinder= pier^2h=pie(d/2)^2h= 24.6556 cm^3 d= square root 4 x 24.6556cm^3/ pie x 20.0 cm =1.25 cm
What is the correct IUPAC name for VF₃?
Vanadium(III) fluoride
The number 3780000 written in scientific notation would be
When converting a number to scientific notation, the decimal place is moved once for each power of 10 in the original number to leave only one number before the decimal point. If the original number is greater than 1, then the decimal place is moved to the left and the exponent in the ×10 indicates how many times the number needs to be multiplied by 10. 3780000=3.78×10×10×10×10×10×10=3.78×106
The number 98000 written in scientific notation would be
When converting a number to scientific notation, the decimal place is moved once for each power of 10 in the original number to leave only one number before the decimal point. If the original number is greater than 1, then the decimal place is moved to the left and the exponent in the ×10 indicates how many times the number needs to be multiplied by 10. .98000=9.8×10×10×10×10=9.8×104
The number 0.00000620 written in scientific notation would be
When converting a number to scientific notation, the decimal place is moved once for each power of 10 in the original number to leave only one number before the decimal point. If the original number is less than 1, then the decimal place is moved to the right and the exponent in the ×10 indicates how many times the number needs to be divided by 10. 0.00000620=6.20÷10÷10÷10÷10÷10÷10=6.20×10−6
The number 0.000741 written in scientific notation would be
When converting a number to scientific notation, the decimal place is moved once for each power of 10 in the original number to leave only one number before the decimal point. If the original number is less than 1, then the decimal place is moved to the right and the exponent in the ×10 indicates how many times the number needs to be divided by 10. 0.000741=7.41÷10÷10÷10÷10=7.41×10−4
The gas produced when sodium metal is added to liquid water is
hydrogen
Before it has been supported by evidence from scientific experimentation, an explanation of a phenomenon is considered to be a
hypothesis