Q: A student is asked to convert $$1.5 \times 10^4$\ \mathrm{mm}^3 to$$ $$\mathrm{m}^3. $$What is the correct answer?

$$1.5 \times 10$$^{-6}$$\ \mathrm{m}^3$$

Question 1

A weather balloon is filled with enough helium to give a volume of 26.5 L at STP. How many grams of helium are in the balloon? (Molar mass of He = 4.00 g/mol, 1 mol gas at STP = 22.4 L)

Accepted Answer

$$3.43\ \mathrm{g}$$

Question 2

You are tasked in the lab to measure out precisely 1.4 L of vibranium, a rare element with a density of $$14.7\ \mathrm{g/cm^3$}. $$What mass (in kg) must you weigh to get the correct volume? (1 L = 1000 cm$$^3)$$

Accepted Answer

$$20.6\ \mathrm{kg}$$

Question 3

What is the molar mass of iron(III) carbonate, $$\mathrm{Fe_2$(CO_3$)_3}$$?

Accepted Answer

$$291.72\ \mathrm{g/mol}$$

Question 4

How many milliliters of 2.5 M KNO$$_3$$ solution can be prepared from 16.5 g of KNO$$_3$$? (Molar mass KNO$$_3$$ = $$101\ \mathrm{g/mol})$$

Accepted Answer

$$65.0\ \mathrm{mL}$$

Question 5

Chloroethane, $$\mathrm{C_2H_5Cl}$$, is used to diagnose dead tooth nerves. Calculate the number of hydrogen atoms in $$3.14\ \mathrm{g} of $$chloroethane. (Molar mass $$\mathrm{C_2H_5Cl}$$ = $$64.5\ \mathrm{g/mol}$$, Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$1.48 	imes 10$$^{23}$$

Question 6

Which of the following is the correct coefficient in front of Na$$_3PO$_4 in $$the balanced equation: $$\mathrm{$$CaCl_2$$ + Na_3PO_4 \rightarrow Ca_3$(PO_4$)_2 + NaCl}$$?

Accepted Answer

$$2$$

Question 7

Upon space exploration, a new element Kneckium (Kn, average mass $$217.8\ \mathrm{amu}) is $$discovered. There are three isotopes: $$^{216}\mathrm{Kn}$$, $$^{217}\mathrm{Kn}$$, and $$^{218}\mathrm{Kn}. $$Which isotope is the most abundant?

Accepted Answer

$$^{217}\mathrm{Kn}$$

Question 8

If you are at a high altitude where the atmospheric pressure is lower than at sea level, what happens to the boiling point of water?

Accepted Answer

It becomes lower because the atmospheric pressure decreases as the altitude rises.

Question 9

You are given a sample of gas at $$1.00\ \mathrm{atm}$$ and $$273\ \mathrm{K} in a$$ $$10.0\ \mathrm{L}$$ container. If the temperature is doubled and the pressure is halved, what is the new volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$40.0\ \mathrm{L}$$

Question 10

A student is asked to convert $$1.5 	imes 10^4$\ \mathrm{mm}^3 to$$ $$\mathrm{m}^3. $$What is the correct answer?

Accepted Answer

$$1.5 	imes 10$$^{-6}$$\ \mathrm{m}^3$$

Question 11

Which of the following best explains why atmospheric pressure decreases as altitude increases?

Accepted Answer

There are fewer air molecules above a given surface as altitude increases.

Question 12

A chemist needs to prepare $$250\ \mathrm{mL} of$$ $$0.100\ \mathrm{M}$$ NaCl solution. How many grams of NaCl are required? (Molar mass NaCl = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$1.46\ \mathrm{g}$$

Question 13

Which of the following statements about Avogadro's number is correct?

Accepted Answer

It is the number of atoms in exactly $$12\ \mathrm{g} of $$carbon-12.

Question 14

A $$5.00\ \mathrm{g}$$ sample of magnesium reacts with excess hydrochloric acid to produce hydrogen gas. How many liters of hydrogen gas are produced at STP? (Molar mass Mg = $$24.3\ \mathrm{g/mol}$$, $$1\ \mathrm{mol}$$ gas at STP = $$22.4\ \mathrm{L}$$, $$\mathrm{Mg + 2HCl \rightarrow $$MgCl_2$$ + H_2$})$$

Accepted Answer

$$2.30\ \mathrm{L}$$

Question 15

Which of the following is a correct statement about the relationship between temperature and the kinetic energy of gas molecules?

Accepted Answer

As temperature increases, the average kinetic energy of gas molecules increases.

General Chemistry I: Exam 1 Study Guide (CHEM121)

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