Q: How many molecules are in $0.250$ moles of $\mathrm{CO}_2$?

$1.51 \times 10^{23}$ molecules

Question 1

A sample of ethanol has a mass of 39.5 g and a volume of 50.0 mL. What is the density of ethanol in $\mathrm{g/mL}$?

Accepted Answer

$0.790\ \mathrm{g/mL}$

Question 2

Which of the following correctly expresses $0.00056$ meters using a metric prefix?

Accepted Answer

$560\ \mu\mathrm{m}$

Question 3

How many atoms of oxygen are present in $2.00$ moles of $\mathrm{CO}_2$?

Accepted Answer

$2.41 	imes 10^{24}$ atoms

Question 4

A student needs $0.250$ moles of sodium chloride ($\mathrm{NaCl}$) for an experiment. What mass of $\mathrm{NaCl}$ should they weigh out? (Molar mass of $\mathrm{NaCl} = 58.44\ \mathrm{g/mol}$)

Accepted Answer

$14.6\ \mathrm{g}$

Question 5

What is the mass percent of hydrogen in water ($\mathrm{H}_2\mathrm{O}$)? (Molar mass: H = $1.01\ \mathrm{g/mol}$, O = $16.00\ \mathrm{g/mol}$)

Accepted Answer

$11.2\%$

Question 6

A block of metal has a density of $8.90\ \mathrm{g/cm}^3$ and a mass of $178\ \mathrm{g}$. What is its volume in $\mathrm{cm}^3$?

Accepted Answer

$20.0\ \mathrm{cm}^3$

Question 7

Convert $0.0035$ kilograms to milligrams.

Accepted Answer

$3,500\ \mathrm{mg}$

Question 8

How many moles of carbon atoms are in $3.00$ moles of $\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$ (glucose)?

Accepted Answer

$18.0$ moles

Question 9

A sample contains $1.20 	imes 10^{24}$ molecules of $\mathrm{NH}_3$. How many moles of $\mathrm{NH}_3$ are present?

Accepted Answer

$1.99$ moles

Question 10

What is the molar mass of $\mathrm{Ca(NO}_3)_2$?

Accepted Answer

$164.10\ \mathrm{g/mol}$

Question 11

A saline solution contains $9.00\ \mathrm{g}$ of $\mathrm{NaCl}$ dissolved in $100.0\ \mathrm{g}$ of solution. What is the mass percent of $\mathrm{NaCl}$?

Accepted Answer

$9.00\%$

Question 12

A chemist has $250.0\ \mathrm{mL}$ of a liquid with a density of $0.789\ \mathrm{g/mL}$. What is the mass of the liquid?

Accepted Answer

$197\ \mathrm{g}$

Question 13

How many nitrogen atoms are in $0.500$ moles of $\mathrm{N}_2\mathrm{O}_5$?

Accepted Answer

$6.02 	imes 10^{23}$ atoms

Question 14

A patient receives $500.0\ \mathrm{mg}$ of a medication. How many grams is this?

Accepted Answer

$0.500\ \mathrm{g}$

Question 15

Which of the following is the correct mole ratio of hydrogen to oxygen atoms in $\mathrm{C}_2\mathrm{H}_5\mathrm{OH}$ (ethanol)?

Accepted Answer

$6:1$

Question 16

A $25.0\ \mathrm{mL}$ sample of a liquid has a mass of $19.8\ \mathrm{g}$. What is its density in $\mathrm{g/mL}$?

Accepted Answer

$0.792\ \mathrm{g/mL}$

Question 17

How many molecules are in $0.250$ moles of $\mathrm{CO}_2$?

Accepted Answer

$1.51 	imes 10^{23}$ molecules

Question 18

A $10.0\ \mathrm{g}$ sample of $\mathrm{CaCl}_2$ contains how many grams of chlorine? (Molar mass: $\mathrm{CaCl}_2 = 110.98\ \mathrm{g/mol}$, Cl = $35.45\ \mathrm{g/mol}$)

Accepted Answer

$6.39\ \mathrm{g}$

Question 19

Which of the following is the correct scientific notation for $0.000072$?

Accepted Answer

$7.2 	imes 10^{-5}$

Question 20

A $100.0\ \mathrm{mL}$ sample of a solution has a density of $1.15\ \mathrm{g/mL}$. What is the mass of the solution?

Accepted Answer

$115\ \mathrm{g}$

Quiz 2 Study Guide: Density, Metric Conversions, Mole Concept, Chemical Formulas, and Mass Percent

Study Guide - Practice Questions

Study Guide - Flashcards