Gen Chem Exam 1
Which of the following quantities represents the greatest volume? A) 300 microliters B) 3.0 x 10^6 nanoliters C) 3.0 x 10^4 deciliters D) 3.0 x 10^-12 kiloliters E) 3.0 milliliters
C. 3.0 x 10^4 deciliters
How many significant figures does the number 48.050 have? A) 3 B) 4 C) 5 D) 2
C. 5
The number 0.00000620 written in scientific notation would be A) 6.20 x 10^-5 B) 6.20 x 10^5 C) 6.20 x 10^-6 D) 6.20 x 10^6
C. 6.20 x 10^-6
How many cubic centimeters are in one cubic meter? A) 100 B) 1,000 C) 10,000 D) 100,000 E)1,000,000
E. 1,000,000 There are 100 cm in 1 meter, therefore there are (100)^3 = 1,000,000cm^3 in 1 m^3
Which of the following is not a defined quantity? A) The speed of light in a vacuum B) The meter C) Absolute zero D) The second E) Barometric Pressure
E. Barometric Pressure Barometric Pressure is measured with a barometer, and varies on weather an location
The net charge on an atom of a given element changes as ________ are added or removed
Electrons
Which scientist developed the nuclear model of the atom?
Ernest Rutherford
The element symbol for fluorine is
F
Which of the following forms of radiation has the highest frequency? A) Red light B) Microwaves C) Ultraviolet rays D) Radio waves E) Gamma rays
Gamma rays
What type of light on the electromagnetic spectrum has the highest energy per photon?
Gamma waves
Red light has a ________ frequency and a __________ wavelength than ultraviolet rays
lower, longer
Rutherford's gold foil experiment determined that
most of the space in an atom is empty except for a concentrated area called the nucleus
Neutral atoms of all isotopes of a given element have the same
number of electrons
What is the mass number for an atom containing 20 protons and 25 neutrons?
45 -The mass number equals the number of protons and neutrons 20+25=45
If the density of a piece of cork is 0.260 g/cm^3, will the item float or sink in pure water? A) Float B) Sink
A. Float
Which of the following represents a species with 39 protons and 36 electrons? A) K+ B) Y C) Ca2+ D) Y3+ E) Ar
Y3+ A plus charge really mean to subtract 3 and vise versa
Determine the mass in grams of 3.00 x 10^21 atoms of arsenic. (The mass of one mole of arsenic is 74.92g)
0.373 g 3.00 x 10^21 atoms of As x 1 mol As/6.022 x 10^23 atoms of As x 74.92 g As/ 1 mol As = 0.373 g As
The number 3780000 written in scientific notation would be A) 3.78 x 10^-5 B) 3.78 x 1065 C) 3.78 x 10^-6 D) 3.78 x 10^6
D. 3.78 x 10^6
A chemist has a block of aluminum metal (density is 2.7 g/mL). The block weighs 1.5g. What is the volume, in mL, of the aluminum block?
0.56 mL D=m/v We are solving for volume so lets rearrange our formula: V=m/d V= 1.5g/2.7 g/mL V=0.56 mL
How many electrons are in a neutral 41Ca atom?
20. Calcium has 20 protons. Therefore has 20 Electrons
What is the mass number for an atom of mercury containing 80 protons and 120 neutrons?
200 -The mass number equals the number of protons and neutrons 80+120=200
Convert 5.5 degrees F to K
258.4 K First, use the formula to convert F to C 5 C= ----- ( F - 32) 9 5 C= ----- ( 5.5F - 32) 9 = -14.72 C Secondly, the formulate convert Celsius to Kelvin is K= C + 273.15 K = -14.72 + 273.15 = 258.4 K
Convert 299.1 K to degrees C
26 degrees C The formula to convert Kelvin to Celsius is C= K - 273.15 C= 299.1 K - 273.15 = 26.0 degrees C
A full truckload of garbage has a mass of 26370 pounds. What is this mass in kilograms?
26370lb 0.4536kg --------- x ------------ = 11960 kg 1 1lb
How many protons are in an element of Co
27 -The atomic number represents the number of protons in an atom
How many hydrogen atoms are in 3 formula units of ammonium benzoate, C6H5COONH4?
27 9 X 3
A molecular cluster is formed from iron atoms and carbon monoxide (CO) molecules. If the molar mass of a cluster is 503.6 g/mol, and its empirical formula is Fe(CO)4, how many iron atoms does the cluster contain?
3
Which of the following statements about subatomic particles are false? 1. Some atoms do not have any neutrons 2. Protons and neutrons reside in the nucleus 3. Some atoms do not have any protons
3 only -All atoms have protons
A particular person in America uses 311.0 gallons of water in a given day. How many liters of water is this?
311.0 gal 3.785L ------------- x ----------= 1177L 1gal 1gal
A chemist has a block of gold metal (density is 19.3 g/mL). They drop the metal into a graduated cylinder containing water, and find the volume change is 1.90 mL. What is the mass of the block in grams?
36.7g D=m/v We are solving for mass, so let's rearrange our formula: M= d x v M= 19.3g/mL x 1.90 mL M= 36.7 g
How many protons are in an atom of Strontium-90
38. Strontium has an atomic number of 38. The atomic number is the number of protons in an atom.
An athlete preparing for a marathon runs 42.5 miles. How many kilometers did they run?
42.5mi 1.0609km ----------- x ----------- = 68.4 km 1mi 1mi
What is the atomic number for an element whose mass number is 115, which contains 66 neutrons per atom?
49 115-66=49
A photon has a frequency of 8.6 x 10^8 Hz. What is the energy of this photon?
5.72 x 10^-24 E= hv E= (6.626 x 10^-34 J x s)(8.6 x 10^8 1/s)
Columns on the periodic table are known as
Groups
The Millikan oil drop experiment determined:
The charge of the electron
The cathode ray tube experiment determined:
The existence of electrons
How Manu neutral atoms 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.
The smallest building block of matter is a(n)
atom
A molar mass value is equivalent to any elements__________
atomic weight
Which of the following temperatures is the coldest? A) 100K B) 100 degrees C C) 100 degrees F
A. 100K
Which of the following numbers contains five significant figures? A) 50.260 B) 0.07246 C) 9935.10 D) 1000.01 E) 2.02470
A. 50.260
If the frequency of an electromagnetic wave increases, the wavelength will ___________
decrease
Density of a substance is its mass per unit volume. If the mass remains constant, what happens to the density of the object? A) The density will increase B) The density will decrease C) Density will stay the same
A. Density will increase
A gold bar is an example of a(n) A) Element B) Compound C) Mixture
A. Element
An iron nail is an example of a(n) A) Element B) Compound C) Mixture
A. Element
Helium filling a balloon is an example of a(n) A) Element B) Compound C) Mixture
A. Element
Neon gas in lights is an example of a(n) A) Element B) Compound C) Mixture
A. Element
Sample of copper is an example of a(n) A) Element B) Compound C) Mixture
A. Element
How do you convert Celsius to Fahrenheit? A) Multiply by 9/5 and then add 32 B) Subtract 273.15 C) Subtract by 32, then multiply by 5//9 D) Add 273.15 E) Celsius is always the same as Kelvin
A. Multiply by 9/5 and then add 32
Which of the following is an example of an intensive property of a gold bar? A) The bar has a density of 19.2 g/mL B) The mass of the bar is 11.4 kg C) The volume of the bar is 218 L D) The bar contains 10^28 atoms
A. The bar has a density of 19.2 g/mL An intensive property is one that does not depend on the amount of the substance measured
The element symbol for copper is
Cu
Energy of a photon is ___________ proportional to frequency, and ___________ proportional to wavelength A) directly, directly B) inversely, inversely C) directly, not D) directly, inversely E) inversely, directly
D
Which of the following is a physical change? A) Magnesium reduces dry ice, forming black carbon and MgO B) Water forms hydrogen and oxygen gases vis electrolysis C) The pH of water is raised by dissolving sodium hydroxide D) Ice forms as water is poured onto dry ice E) Water hydrates cobalt chloride, turning it from blue to pink
D. Ice forms as water is poured onto dry ice
Which of the following is an example of an extensive property of copper nugget? A) It is copper colored B) It has a density of 8.96 g/cm^3 C) It has a melting point of 1085 degrees C D) It has a mass of 52.3 g
D. It has a mass of 52.3 g An extensive property is one that depends on the amount of the substance present
You have a 100g sample of each of the following metals. Which sample has the largest volume? A) Aluminum, d= 2.7g/cm^3 B) Gold, d= 19.3 g/cm^3 C) Iron, d= 7.86 g/cm^3 D) Magnesium, d= 1.74 g/cm^3 E) Silver, d= 10.5 g/cm^3
D. Magnesium, d= 1.74 g/cm^3
Gasoline is composed of a variety of different liquid hydrocarbons, which do not separate as time passes. Gasoline is an example of a: A) heterogenous mixture B) Chemical compound C) Chemical element D) Solution
D. Solution
Kelvin is the SI unit for which physical quantity? A) mass B) length C) time D) temperature
D. Tempurature
Which of the following is an extensive property of the element carbon? A) Its boiling point B) The temperature of a carbon sample C) Its freezing point D) The mass of a carbon sample E) Its density
D. The mass of a carbon sample
Which of the following is a pure substance that can be broken down into simpler substances by chemical means? A) element B) homogeneous mixture C) solution D) compound E) heterogeneous mixture
D. compound
Density is defined as mass ___________ volume A) added to B) subtracted from C) multiplied by D) divided by
D. divided by
Which of the following are chemical properties of matter? A) mass B) volume C) density D) flammability
D. flammability
A human is an example of a(n) A) element B) compound C) homogeneous mixture D) heterogenous mixture
D. heterogenous mixture
Which one of the following is an example of an element? A) concrete B) salt C) steel D) iron
D. iron
Which of these represents a CHEMICAL change? A) lard when heated changes to liquid B) water disappears from a beaker in a few days at room temperature C) sugar dissolving in water D) milk turns sour after sitting at room temperature for a few days E) water boils below 100 degrees C on a mountain
D. milk turns sour after sitting at room temperature for a few days
The element symbol for lead is
Pb
The nucleus of an atom contains:
Protons and neutrons
Does a proton or electron have a greater mass?
Protron
Which two particles of the atom have nearly identical masses?
Protron and neutron
Which scientist determined the charge of the elctron?
Robert Millikan
What element with a mass number of 100 has 56 neutrons in its nucleus?
Ruthenium -100= x + 56 44 = x Find the element on the periodic table that contains 44 protons
Which of the following best categorizes Newton's conclusions on universal gravitation?
Scientific Law
The element symbol for tin is
Sn
If the amplitude of an electromagnetic wave increases, the frequency will _____________
Stay the same
If the frequency of an electromagnetic wave decreases, the amplitud will
Stay the same
What hypotheses of Dalton's atomic theory are not true?
-All atoms of a given element are identical -Atoms are indestructible
What are Dalton's hypotheses of atomic theory?
-Elements are composed of atoms -Compounds are composed of atoms of more than one chemical element -A chemical reaction involves the rearrangement of atoms -All atoms of a given element are identical
Which of the following atoms has the same number of neutrons as 59Ni? A) 57Co B) 58Fe C) 58Ni D) 59Co E) 60Co
-Nickel has an atomic number of 28, which means that it contains 28 protons and 31 neutrons 59= 28 + x 31= x -60Cu has a mass number of 60 and an atomic number of 29. It also has 31 neutrons 60= 29 + x 31= x
The element antimony (Sb) has an atomic mass of 121.76 amu. Two naturally occurring isotopes of antimony are 121Sb (57% abundant) and 123Sb (43% abundant). In a sample of 100 Sb atoms, what is the probability that a single selected atom has a mass of 121.76 amu? A) 0% B) 43% C) 57% D) 100% E) Not possible to determine
0% -The atomic mass is an average that represents the abundance of each isotope. No individual atom has this mass
Which of the following statements about subatomic particles are true? 1. Protons and electrons have charges of opposite signs but the same magnitude 2. Protons have twice the mass of neutrons 3. Electrons are lighter than neutrons
1 and 3 only. -Protons and electrons have charges of opposite signs but the same magnitude -Electrons are lighter than neutrons
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 4.5 g, what is the density of the metal in g/mL?
1.1g/mL D= m/v D= 4.5g/4.1 mL D= 1.0976 g/mL Round to 1.1
How many carbon atoms are in 19 molecules of benzene, C6H6?
114 19 x 6
Determine the number of proton and electrons in Mg2+
12 protons and 10 electrons Subtract 2 from 12 to get electrons Mg has an atomic number of 12 so there are 12 protons. Because the ion has a +2 charge, this indicates that there are two fewer electrons.
What is the mass number of tin-120
120 -indicates an atom of tin with a mass number of 120
An unknown element X has the following isotopes: 126X (22.00% abundant), 128X (34.00% abundant), 130X (44.00% abundant). What is the average atomic mass in amu of X?
128.44 amu Multiply the mass # for each isotope by its abundance in decimal form and adding them together. (0.2200 x 126amu) + (0.3400 x 128amu) + (0.4400 x 130 amu) = 128.44 amu
What is the mass number for an atom containing 56 protons and 82 neutrons?
138 -The mass number equals the number of protons and neutrons 56+82=138
How many neutrons are in an atom of Uranium-235
143. Uranium has 92 protons. Therefore, uranium -235 has 143 neutrons.
What is the mass number of platinum-194
194 -indicates an atom of tin with a mass number of 194
Which of the following statements about subatomic particles are false? 1. Neutrons reside inside the nucleus 2. The atomic number is equal to the number of neutrons in the nucleus of an atom 3. Electrons are more massive than protons
2 and 3 only. -The atomic number is equal to the number of protons in the nucleus of an atom -Protons are more massive than electrons
Which of the following statements about subatomic particles are true? 1. Protons and neutrons have charges of opposite signs but the same magnitude 2. Protons and neutrons have about the same mass 3. A neutral atom has the same number of neutrons and electrons
2 only -Protons and neutrons are approximately the same mass
A hot air balloon's gondola is suspended below a cloth envelope containing 2.775 x 10^6 liters of hot air. How many milliliters of hot air is this?
2.775 x 10^6L 1000 mL --------------- x ------------ = 2.775 x 10^9 mL 1 1L
The green light emitted by a stoplight has a wavelength of 505nm. what is the frequency of this photon? (c= 3.00 x 10^8 m/s)
5.9405 x 10^14 Hz 1st, convert nm to m: 505nm 1nm ------------- x ----------- = 505 x 10^-9 1 10^9nm Frequency (v) of a photon is equal to the speed of light (c) divided by the wavelength (λ) 3.00 x 10^8 m x s^ -1 -------------------------- = 5.94 x 10^14 s^-1 505. x 10^-9 m
An atom of the isotope 133Cs contains how many protons, neutrons, and electrons?
55p, 78n, 55e -Look at the periodic table to find the number of protons
What is the atomic number for an element whose mass number is 138, which contains 81 neutrons per atom?
57 138-81=57
How many electrons are in a neutral Carbon-14 atom?
6. 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.
Determine the number of protons and electrons in N3-
7 protons and 10 electrons Add 3 to 7 to get the electrons
An unknown element is a mixture of isotopes 120X and 122X. The average atomic mass of X is 121.47 amu. What is the percent abundance of 122X?
73.5% Set their weighted average equal to the average atomic max and solve for x. 122(x)amu + 120(1-x)amu = 121.47 (122 -120)x = 121.47 - 120 x=121.47-120/122-120=1.47/2= 0.735 Convert fraction to percent = 73.5%
Consider bromine, which occurs as a mixture of two isotopes: bromine-79, with a natural abundance of 50.7% and an exact mass of 78.92amu. And bromine-81, with a natural abundance of 49.3% and an exact mass of 80.92 amu. What is the average atomic mass of bromine?
79.9amu (78.92amu x 0.507) + (80.92amu x 0.493) = 79.9amu
Food safety guidelines recommend that a beef rib roast (bone-in) should cook for 23.0 minutes per pound based on a 325 degrees F oven setting. How many hours should it take to cook a 8.21 pound roast?
8.21lb 23.0min 1hr ---------- x ----------- x ---------- = 3.15 hours 1 1lb 60min
An irregularly-shaped piece of tin (Sn) has a mass of 65.0 grams. What is the volume in cm^3 of this piece of tin if its density is 7.30 g/cm^3?
8.9cm^3 65.0g 1cm^3 ------ x ---------- = 8.90 cm^3 1 7.30g
A cup of coffee contains 95.0 milligrams of caffeine. How many grams is this?
95.0 mg 1g --------- x --------- = 0.0950 g 1 1000mg
Wavelength as it relates to an electromagnetic wave is defined as which of the following? A) Wavelength is the distance between two consecutive peaks or troughs in a wave B) Wavelength corresponds to the magnitude of the wave's distance C) Wavelength is the number of wave cycles that pass a specified point in space
A
Which of the following represents an exact quantity? A) There are 2.54 cm in an inch B) A man is 5 feet 10 inches tall C) A man weighs 200lbs D) It takes 15 minutes to drive to the grocery store E) There are 80 grams of sugar in a serving of soda
A. There are 2.54 cm in an inch
Density of a substance is defines as its mass per unit volume. If the mass of the object increases, what must the volume do in order for the density to stay the same? A) Volume must increase B) Volume must decrease C) Volume remains the same
A. Volume must increase
Which of the following is a chemical change? A) cooking an egg B) mixing oil and water C) tearing a piece of paper D) watching a DVD
A. cooking an egg
Calcium is an example of A) element B) compound C) homogeneous mixture D) heterogenous mixture
A. element
Italian dressing contains olive oil and vinegar, which will separate out from each other if left to sit. This makes the dressing a: A) heterogeneous mixture B) homogenous mixture C) both A and B D) None of the above
A. heterogeneous mixture
A homogeneous mixture is also called a A) solution B) pure substance C) heterogeneous mixture D) liquid
A. solution
Which color (frequency) of light travels the fastest in a vacuum?
All have the same speed
An atom has nine protons and ten electrons. This makes it
An ion
The element symbol for arsenic is
As
The element symbol for gold is
Au
Define amplitude as it relates to an electromagnetic wave A) Amplitude is the distance between two consecutive peaks or troughs in a wave B) Amplitude corresponds to the magnitude of the wave's height C) Amplitude is the number of wave cycles that pass a specified point in space
B
Which of the following would be an isotope for 14N A) 14C B) 16N C) 14N D) 16O E) All of the above
B) 16N -Same element, different number of protons and neutrons. Same number of protons and electrons.
Which of the following quantities is equivalent to 3.7cm? A) 3.7 x 10^-3m B) 3.7 x 10^-5km C) 3.7 x 10^-2mm D) 3.7 x 10^5 E) 3.7 x 10^2 mm
B. 3.7 x 10^-5km
The number 0.000741 written in scientific notation would be A) 7.41 x 10^4 B) 7.41 x 10^-4 C) 7.41 x 10^3 D) 7.41 x 10 ^-3
B. 7.41 x 10^-4
Which of the following best defines a scientific theory? A) An 'if, then' statement that can be tested by science. B) A model used to explain how or why a phenomenon occurs C) A unifying concept; often a mathematical description of the way in which a natural phenomenon occurs D) A piece of knowledge about the outside world received through the senses or instrumentation E) Something that is known to be consistent with reality; that which has not been falsified
B. A model used to explain how or why a phenomenon occurs
Baking soda (sodium bicarbonate) is an example of a(n) A) Element B) Compound C) Mixture
B. Compound
Glucose is an example of a(n) A) element B) compound C) homogeneous mixture D) heterogenous mixture
B. Compound
You have a 100g sample of each of the following metals. Which sample has the smallest volume? A) Aluminum, d= 2.7g/cm^3 B) Gold, d= 19.3 g/cm^3 C) Iron, d= 7.86 g/cm^3 D) Magnesium, d= 1.74 g/cm^3 E) Silver, d= 10.5 g/cm^3
B. Gold, d= 19.3 g/cm^3
Which one of the following would be a chemical property of a sample of neon gas? A) It is a gas at room temperature B) It is inert C) It is colorless D) It boils at -246 degrees C
B. It is inert If a property (being inert) can not be measured without chemically changing the substance, its a chemical property
The law of conservation of mass is best described as which of the following statements? A) The total energy of the universe is constant B) Matter can neither be created nor destroyed C) Energy equals mass times the speed of light squared D) For every action, there is an equal and opposite reaction E) Mass can only decrease as a result of a chemical reaction
B. Matter can neither be created nor destroyed
If the density of a piece of high density polyurethane is 1.05 g/cm^3, will the item float or sink in pure water? A) Float B) Sink
B. Sink
Which of the following metric prefixes corresponds to 10^3 A) centi- B) kilo- C) mega- D) micro- E) milli-
B. kilo-
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? A) solid B) liquid C) gas
B. liquid
What is the name of the SI unit for length? A) kilogram B) meter C) second D) Kelvin
B. meter
Which of the following is an example of an element? A) brass B) nickel C) bronze D) sterling silver
B. nickel
Define frequency as it relates to an electromagnetic wave A) Frequency is the distance between two consecutive peaks or troughs in a wave B) Frequency corresponds to the magnitude of the wave's height C) Frequency is the number of wave cycles that pass a specified point in space
C
Which of the following pairs represent isotopes? A) 28Si and 28Si4+ B) 28Si and 28AI C) 28Si and 29Si D) 28Si and 28Si4- E) 28Si4+ and 28AI3+
C) 28Si and 29Si -Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons
Which of the following best defines a scientific law? A) An 'if, then' statement that can be tested by science. B) A model used to explain how or why a phenomenon occurs C) A unifying concept; often a mathematical description of the way in which a natural phenomenon occurs D) A new occurrence that cannot be explained using what is currently scientifically known E) Something that is known to be consistent with reality; that which has not been falsified
C. A unifying concept; often a mathematical description of the way in which a natural phenomenon occurs
A chemist is trying to identify an unknown metal, and finds that 25.0 cm^3 of the substance has a mass of 224.43g at 20 degrees C. Which of the following metals is it? A) Aluminum, d= 2.70 g/cm^3 B) Iron, d= 7.87 g/cm^3 C) Copper, d= 8.98 g/cm^3 D) Silver, d=10.5 g/cm^3 E) Gold, d= 19.32 g/cm^3
C. Copper, d= 8.98 g/cm^3 D= m/v 224.43g/25.0cm^3 = 8.98 g/cm^3
Which of the following are physical properties of matter? A) stability B) reactivity C) density D) flammability
C. Density
Which of the following describes a chemical change involving water? A) H2O(l) to H2O (s) B) H2O (s) to H2O (g) C) H2O (l) to H2(g0 + 1/2 O2(g) D) H2O(g) to H2O(l)
C. H2O (l) to H2(g0 + 1/2 O2(g) A chemical change would involve the atoms found in a water molecule rearranging to form a new molecule of molecules with different composition(s)
Water and laundry detergent are mixes together, with detergent molecules dispersing uniformly throughout the liquid. This is an example of a A) mixture of elements B) heterogeneous mixture C) homogeneous mixture (solution) D) molecular compound
C. Homogeneous mixture (solution)
Which one of the following would be a physical property of glucose? A) It is used by the body to generate energy B) When combined with sulfuric acidic forms carbon C) In its pure form, it is a white powder D) It can be fermented to form alcohol
C. In its pure form, it is a white powder
A bar of soap is an example of a(n) A) Element B) Compound C) Mixture
C. Mixture
When methane is completely combusted in oxygen forming carbon dioxide and water, how does the mass of the reactant gases compare to the products? A) The reactants have greater mass B) The products have greater mass C) The masses of the reactants and products are equal D) The mass of the reactants cannot be determined E) Depending on reaction conditions, the total mass could increase or decrease
C. The masses of the reactants and products are equal
Which of the following is a physical change? A) An alkaline battery is discharged B) A lithium-ion battery is recharged C) Water is boiled in a microwave D) A car battery is jump-started E) A pinch of salt is dissolved in water
C. Water is boiled in a microwave
Which of the following is a step that is NOT in the scientific method? A) making observations B) formulating hypotheses C) modifying laws D) performing experiments
C. modifying laws
Determine the empirical formula for C6H14O
C6H14O, Cannot be reduced any further. Not all three terms can be simplified
What is the definition of a scientific law?
It summarizes an observable behavior
The element symbol for potassium is
K
The element symbol for manganese is
Mn
The atomic mass of germanium (Ge) on the periodic table is 72.630 amu. Which of the following best explains why the atomic mass is a fraction between 72 and 73? A) The presence of different isotopes B) The presence of different isomers C) The formation of different ions D) The presence of different allotropes E) The presence of different amounts of protons
The presence of different isotopes
The process of evolution of species as described by Darwin is best thought of as: A) Theory B) Law C) Hypothesis D) Observation E) Fact
Theory
Does a proton or electron have a greater magnitude of charge?
They have equal charges
What does the mass number of an atom represent?
Total number of protons and neutrons in the atom
Light wave A has a greater frequency than light wave B. Which has a greater wavelength? A) Wave A B) Wave B C) They're equal D) Not enough info
Wave B