CHEM 1 terms

Which of the following contains the most moles of atoms?

1 g of helium *To convert from grams to moles, you need to divide by the molar mass. Since each of these options has the same mass, dividing by the smallest molar mass will yield the most moles of atoms. Since helium has a lower molar mass (4 g/mol) than carbon (12 g/mol) or uranium (238 g/mol), it must contain the most moles.

Determine the number of atoms in 43.0 grams of sodium, Na. (The mass of one mole of sodium is 22.99 g.)

1.126 x 10^23 *43.0 g/ 22.99 g/mol = 1.870 mol Na 1.870 mol Na x (6.022 x 10^23) = 1.126 x 10^23

A pycnometer is a glass flask with a tight fitting glass stopper that is used to obtain the volume of a liquid with high accuracy. A pycnometer has a mass of 25.151 grams when empty, and a mass of 42.481 grams when completely filled with water. The pycnometer has a mass of 48.629 when completely filled with an unknown liquid. What is the density of the unknown liquid? Assume the density of water is 1.000 g/cm³.

1.3548 g/cm^3 *mass of water in pycnometer: 42.481 - 25.151 = 17.330 g mass of unknown in pycnometer: 48.629 - 25.151 = 23.478 g.........28.478 g/ 17.330 g = 1.3548 g/cm^3

How many atoms of vanadium (v) are in 1.28 grams of vanadium?

1.51 x 10^22 *1.28 g V (1 mol V/ 50.94 g V) (6.022 x 10^23 atoms V/ 1 mol V) = 1.51 x 10^22

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

1000

How many atoms of zirconium are in 0.3521 mol of ZrSiO4?

2.120 x 10^23 *0.3521 mol ZrSiO4 (1 mol Zr/ 1 mol ZrSiO4) (6.022 x 10^23 atoms Zr/ 1 mol Zr) = 2.120 x 10^23

Determine the number of atoms in 30.0 g of Zn.

2.758 x 10^23 *30.0 g / 65.39 g/mol = 0.458 mol Zn 0.458 mol Zn (6.022 x 10^23) = 2.758 x 10^23

Chlorine exists in nature as a mixture of two stable isotopes, Cl-35 and Cl-37. If the atomic mass of chlorine is given as 35.45 amu, which of the following represents the percent abundance of Cl-37?

23% *(35)(1−x)+(37)(x)=35.45 35−35x+37x=35.45 2x=0.45 x=0.225

A race car has a maximum speed of 0.104 km/s. What is this peed in miles per hour?

233 mi/hr *0.104 km/s (60 s/ 1 min) (60 min/ 1 hr) (0.6214 mi /1 km) = 233 mi/hr

Convert 5.1 F to K

258.21 K *convert to C first = -14.94 and plug into K equation K = -14.94 + 273.15 = 258.21

A cooking recipe lists adding 3.0 qt of water as a step. How many mL of water is this?

2800 mL *3.0 qt (1 gal/ 4 qt) (3.785 L/ 1 gal) (1000 mL/ 1 L) = 2800 mL

A thermometer reads 22.9 C. What is the temperature in Kelvin?

296.05 K * K = C + 273.15 K= 22.9 + 273.15 = 296.05 K

How many miles can you drive if your car gets 24.7 miles per gallon and you have 12.0 gallons of gas

296.4 miles *12.0 gal (24.7 miles/1gal) = 296.4 miles

Which of the following quantities represents the greatest volume? 1) 300 microliters 2) 3.0 x 10^6 nanoliters 3) 3.0 x 10^4 deciliters 4) 3.0 x 10^-12 kiloliters 5) 3.0 milliliters

3.0 x 10^4 deciliters *a deciliter is equal to 1/10 of a liter. Therefire, 3 x 10^4 or 30,000 deciliters is equal to 3,000 liters, which if 3,000,000 mL.

Which of the following quantities is equivalent to 3.7 cm?

3.7 x 10⁻⁵ km

The number 3,780,000 in scientific notation would be...

3.78 x 10^6

A liquid in the lab has a density of 1.24 g/cm^3. What is the mass in grams of 254 mL of the liquid?

315 g *254 mL (1 cm^3/ 1mL) (1.25 g/ 1 cm^3) = 315 g

An athlete preparing for a marathon runs 21.3 miles. How many kilometers did they run?

34.3 km * 21.3 mi (1.609 km/ 1 mi) = 34.3 km

You are renting a car which is reported to achieve 16.9 km/L. What is its mileage in miles/gal?

39.75 miles/gal *16.9 km/ 1L (0.6213 miles/ 1 km) (1 L/ 0.2641 gal) = 38.75 miles/gal

How many sfs would the following equation have: (9.04 -8.23 + 21.954 + 81.0) x 3.1416 1) 3 2) 4 3) 5 4) 6

4 *when the operations have been done, you are left with 103.764 x 3.1416 = 325.98498, which would be rounded to 326.0

Calculate the mass, in grams, of 492 atoms of iron, Fe (1 mol of Fe has a mass of 55.85 g).

4.56 × 10⁻²⁰ g *The mass of a substance can be calculated from its number of atoms using Avogadro's number and its molar mass. For example, 492 Fe atoms (1 mol Fe/ 6.022×10^23 Fe atoms) (55.85 g Fe/ 1 mol Fe) = 4.56 × 10⁻²⁰ g

A chemist has a block of aluminum metal (density 2.7 g/ml). They drop the metal into the graduated cylinder containing water and find the volume change is 1.7 mL. What is the mass of the block, in grams?

4.6 g *m = dv m= 2.7 g(1.7 g) = 4.59 g (2sf) = 4.6 g

An unknown element X has the following isotopes: ⁵²X (85.50% abundant), ⁴⁹X (8.00% abundant), ⁵⁰X (6.50% abundant). What is the approximate atomic mass of X?

51.37 amu *[(52x85) + (49x8) +(50x6.50)]/100 5137/100 = 51.37 amu

An unknown element X has the following isotopes: ⁵²X (90.00% abundant), ⁴⁹X (8.00% abundant), ⁵⁰X (2.00% abundant). What is the approximate atomic mass of X?

51.72 amu *[(52x90) + (49x8) + (50x2)]/100 (4680 + 392 + 100)/100 5172/100 = 51.72

An atom of the isotope ¹³³Cs contains how many protons (p), neutrons (n), and electrons (e)?

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. 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

A particular medication dosage is 45.0 mg/kg of body weight. How many mg of the medication should a child weighing 29.2 lbs receive?

589.5 mg *Convert lbs to kg 29.1 lb (1 kg/ 2.20462 lb) = 13.1 kg 13.1 x 45 = 589.5 mg

What is the value of Avogadro's number?

6.0221415 × 10²³

Convert 7.54 x 10^-8 meters to nanometers.

75.4 nm *7.54 x 10^-8 m (1 nm/ 10^-9 m) = 75.4 nm

A thermometer reads 24.5 C. What is the temperature in Fahrenheit?

76.1 F

The halogens are found in Group _________

7A (17)

The number 875,000 in scientific notation would be...

8.75 x 10^5

Determine the mass, in grams, of 0.395 moles of Pb (1 mol of Pb has a mass of 207.2 g).

81.84 g *0.395 moles Pb (207.2 g Pb/ 1 mol Pb) = 81.84 grams

Convert 2.3 hours into seconds

8280 seconds *2.3 hours (60 min/ 1 hour) (60 seconds/ 1 min) = 8280 seconds

The number 98,000 in scientific notation would be...

9.8 x 10^4

Convert 26.4 gallons to deciliters (3.7854 liters = 1 gallon)

999.3487 dL *26.4 gal (3.7854 L/ 1 gal) (10 dL/ 1L) = 999.3487 dL

What is the element symbol for aluminum?

Al

Which of the following elements is NOT a metal?

Arsenic (Ar) *Arsenic is an element on the "staircase" on the Periodic Table, making it a metalloid, not a metal.

A mole equals any elements ____________

Atomic weight *The mass of one mole of carbon atoms is equal to its atomic mass.

Submicroscopic particles which are the building blocks of matter

Atoms

Which of the following is an alkaline earth metal?

Beryllium (Be) *The alkaline earth metals are found in Group 2 and include Be, Mg, Ca, Sr, Ba, and Ra.

Which element has the symbol F

Fluorine

Columns on the periodic table are known as _______

Groups

Which of the following is a halogen?

Iodine (I) *The halogens are found in Group 17 and include F, Cl, Br, I, At, and Ts.

A mass spectrometer measures neon to have two masses: 20 and 22 atomic mass units. These are:

Isotopes *Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons. This yields atoms of the same element that have different masses.

The element symbol for potassium is _____

K

A physical combination of two or more substances which can be separated into its original components

Mixture

Neutral atoms of all isotopes of a given element have the same

Number of electrons *Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons and electrons.

Which of the following is NOT a metalloid?

Pb (lead) *Metalloids are elements that have properties of both metals and nonmetals. Lead (Pb) is a metal. The metalloids are: B, Si, Ge, As, Sb, Te and Po

The nucleus of an atom contains...

Protons and neutrons

Which two particles of the atom have nearly identical masses?

Protons and neutrons *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 element with a mass number of 100 has 56 neutrons in its nucleus

Ruthenium (Ru) *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 atomic symbol for the element in Group 5A (15) and the fifth period?

Sb (Antimony)

Which of the following is NOT an alkali or alkaline earth element? *The alkali metals are found in Group 1 (column 1) and the alkaline earth metals are found in Group 2 (column 2). Sc is found in Group 3 (column 3).

Sc (Scandium)

Which of the following sets of elements and symbols is paired incorrectly?

Silver, Si *The Periodic Table provides element names and symbols. Silver has the element symbol "Ag". It was originally named argentum.

Which of the following sets of elements and symbols is paired incorrectly?

Sodium, S *The Periodic Table provides element names and symbols. Sodium has the element symbol "Na". The "Na" comes from the Latin word "natrium".

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?

The presence of different isotopes *The atomic mass is an average that represents the abundance of each isotope

What is the atomic symbol for the element in Group 4B (4) and the fourth period?

Ti (Titanium)

What does the mass number of an atom represent?

Total number of protons and neutrons in the atom

Magnesium metal, a gray solid, is heated in a crucible in the presence of oxygen. A white powder is collected from the crucible. This is an example of... 1) a chemical change 2) a separation 3) a mixture 4) a physical change

a chemical change

If you go mini-golfing, in which of these scenarios are you precise but not accurate? 1) you hit all holes in one 2) you take six strokes at each hole 3) it always takes you a long time to get your shots in 4) all of your shots are off, but they all go to the same place

all of the your shots are off, but they all go to the same place

Which one of the following is an example of a homogenous mixture? 1) coffee 2) iron 3) salt 4) concrete

coffee

Which of the following is a chemical change? 1) cooking an egg 2) mixing oil and water 3) tearing a piece of paper 4) watching a DVD

cooking an egg

A chemist is trying to identify an unknown metal, and finds that 25.0 cm^3 of the substance has a mass of 224.43 g at 20 C. Which of the following metals is it? 1) aluminum, d = 2.70 g.cm^3 2) iron, d = 7.87 g.cm^3 3) copper, d = 8.98 g/cm^3 4) silver, d = 10.5 g/cm^3 5) gold, d = 19.32 g/cm^3

copper *Density is an intensive property and is the ratio of mass to volume *d = m/v 224.43 g/25.0cm^3 = 8.98 g/cm^3

Which of the following are physical properties of matter?

density

Density is defined as mass ___________ volume. 1) added to 2) subtracted from 3) multiplied by 4) divided by

divided by

Which one of the following is not an example of a physical change? 1) distilled water to remove impurities 2) filtration of sand out of water 3) mixing water and sugar 4) electrolysis of water to form hydrogen and oxygen gas

electrolysis of water to form hydrogen and oxygen gas

Which of the following are chemical properties of matter? 1) mass 2) volume 3) density 4) flammability

flammability

Which one of the following is an example of an element? 1) concrete 2) salt 3) steel 4) iron

iron

Which of the following is an example of an extensive property of copper nugget? 1) it is copper colored 2) it has a density of 8.96 g/cm3 3) it has a melting point of 1085 C 4) it has a mass of 52.3 g

it has a mass of 52.3 g

Which of the following is an intensive property of a sample of neon gas? *Intensive - a property that does not depend on the amount of matter involved 1) its mass 2) the number of neon atoms present 3) its temperature 4) its volume 5) the number of moles of neon atoms present

its temperature

Which of the following is an extensive physical property of matter? *Extensive - a property that depends on the amount of matter involved 1) boiling point 2) reactivity 3) density 4) length e) freezing point

length

You have a 100 gram sample of each of the following metals. Which sample has the largest volume? *the sample with the lowest density would have the greatest volume 1) aluminum, d= 2.7 g/cm^3 2) gold, d = 19.3 g/cm^3 3) iron, d = 7.86 g/cm^3 4) magnesium, d = 1.74 g/cm^3 5) silver, d = 10.5 g/cm^3

magnesium

What is the name of the SI unit for length? 1) kilogram 2) meter 3) second 4) Kelvin

meter

Which one of these represents a chemical change? 1) lard when heated changes to liquid 2) water disappears from a beaker in a few days at room temperature 3) sugar dissolves in water 4) milk turns sour after sitting at room temperature for a few days 5) water boils below 100 C on a mountain

milk turns sour after sitting at room temperature for a few days

Some liquid in a jar can be separated by physical means into two separate liquids, which can the be separated no further. The liquid is a(n)...

mixture

The density of water is approximately 1 g/cm^3. Which of these objects will SINK in water? 1) liquid hydrogen, d = 0.070 g/cm^3 2) lithium, d = 0.535 g/cm^3 3) potassium, d = 0.860 g/cm^3 4) polymer resin, d = 1.03 g/cm^3

polymer resin *a density > 1 g/cm^3 will sink

Vegetable oil has a density of 0.92 g/cm^3. Which of these substances would FLOAT on vegetable oil? 1) corn syrup, d = 1.4 g/cm^3 2) mercury, d = 13.6 g/cm^3 3) aluminum, d = 2.7 g/cm^3 4) rubbing alcohol, d = 0.79 g/cm^3 5) water, d = 1.0 g/cm^3

rubbing alcohol *because rubbing alcohol is less dense than vegetable oil, it would float

A homogeneous mixture is also called a...

solution

Gasoline is composed of a variety of different liquid hydrocarbons, which do not separate as time passes. Gasoline is an example of a...

solution

Which of the following is a physical change? 1) rusting of a nail 2) tearing a piece of paper 3) cooking an egg 4) burning wood

tearing a piece of paper

Kelvin is the SI unit for which physical quantity? 1) mass 2) length 3) time 4) temperature

temperature

Which of the following represents an exact quantity? 1) there are 2.54 cm in an inch 2) a man is 5 feet 10 inches tall 3) a man weighs 200 lbs 4) it takes 15 minutes to drive to the grocery store 5) there are 80 grams of sugar in a serving of soda

there are 2.54 cm in an inch

Which of the following quantities is equivalent to 594 mg?

0.594 g

Convert 26.4 inch to meters (2.54 cm 1 inch)

0.67056 m *26.4 in (2.54 cm/ 1 in) (1 m/ 100 cm) = 0.67056

A tank you with 43.2 kg of water is leaking at a rate of 0.0134 kg/s. How many hours will it take until the tank it completely empty?

0.889 hr *43.2 kg (1 s/0.0135 kg) (1 hr/ 3600 s) = 0889 hr

Convert 26.2 milligrams to kilograms

0.0000262 kg

0.085631 x 1.32 = (with correct sf)

0.113 *0.085631 contains 5sfs, 1.32 contains 3sfs

Convert 5.32 x 10^-7 seconds to microseconds. Using only the metric system

0.532 microseconds *5.32 x 10^-7 seconds (1 microsecond/ 10^-6 seconds) = 0.532 seconds

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 and 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? 1) aluminum, d = 2.70 g/mL 2) magnesium, d = 1.74 g/mL 3) tin, d = 5.75 g/mL 4) lead, d = 11.3 g/mL

tin *use given mass but take the difference in the original and new volumes (20.44 mL - 14.78 mL = 5.66 mL) 32.56 g/5.66 mL = 5.75 g/mL (use 3sfs)

Which of these scenarios contains an exact number? 1) you count 10 people in a room 2) you weigh an apple to be 10 grams 3) you measure the tree to be 10 meters high 4) you determine the volume of the pool to be 10 liters

you count 10 people in a room *an exact number is a number that is either defined or can be counted

What is the atomic symbol and mass number for an atom containing 50 protons and 64 neutrons?

¹¹⁴Sn *Find the mass number with 50 + 64 = 114 The atomic number is the protons and electrons since we are given the number of protons is 50, 50 is the atomic number

Which of the following would be an isotope of ¹⁴N?

¹⁶N *Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons and electrons. ¹⁶N is an isotope of ¹⁴N.