Q: A sample contains 4.00 moles of water ($H_2O$). How many molecules of water are present in the sample? (Avogadro's number $= 6.022 \times 10^{23}$)

$2.41 \times 10^{24}$ molecules

Q: Which of the following is a correct metric conversion?

$1 \text{ km} = 1000 \text{ m}$

Q: Which of the following statements about the mole is correct?

A mole contains $6.022 \times 10^{23}$ representative particles of a substance.

Q: Which of the following best describes a limiting reactant in a chemical reaction?

The reactant that is completely consumed first, limiting the amount of product formed.

Question 1

Which of the following statements best describes the difference between an element and a compound?

Accepted Answer

An element is a substance that cannot be broken down into simpler substances by chemical means, while a compound is composed of two or more elements chemically combined in fixed proportions.

Question 2

A sample contains 4.00 moles of water ($H_2O$). How many molecules of water are present in the sample? (Avogadro's number $= 6.022 	imes 10^{23}$)

Accepted Answer

$2.41 	imes 10^{24}$ molecules

Question 3

Which of the following is the correct scientific notation for the number 0.000345?

Accepted Answer

$3.45 	imes 10^{-4}$

Question 4

A student measures the mass of a sample as 12.30 g, 12.28 g, and 12.31 g in three trials. The true mass is 12.00 g. Which statement best describes the accuracy and precision of the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 5

Which of the following is the correct formula for magnesium nitrate?

Accepted Answer

$Mg(NO_3)_2$

Question 6

How many significant figures are in the measurement 0.0045600 g?

Accepted Answer

6

Question 7

Which of the following ions is a polyatomic ion?

Accepted Answer

$SO_4^{2-}$

Question 8

A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is the empirical formula of the compound?

Accepted Answer

$CH_2O$

Question 9

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two nonmetal atoms.

Question 10

Which of the following is a correct metric conversion?

Accepted Answer

$1 	ext{ km} = 1000 	ext{ m}$

Question 11

A sample of sodium chloride ($NaCl$) has a mass of 58.44 g. How many moles of $NaCl$ are present? (Molar mass of $NaCl = 58.44 	ext{ g/mol}$)

Accepted Answer

1.00 mol

Question 12

Which of the following is NOT a diatomic molecule in its natural state?

Accepted Answer

$Ne$

Question 13

What is the charge on the iron ion in $Fe_2O_3$?

Accepted Answer

+3

Question 14

Which of the following best describes the term 'isotope'?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 15

A reaction has a theoretical yield of 10.0 g and an actual yield of 8.0 g. What is the percent yield?

Accepted Answer

$80\%$

Question 16

Which of the following is the correct name for $N_2O_5$?

Accepted Answer

Dinitrogen pentoxide

Question 17

Which of the following statements about the mole is correct?

Accepted Answer

A mole contains $6.022 	imes 10^{23}$ representative particles of a substance.

Question 18

Which of the following is the correct order of subatomic particles in terms of increasing mass?

Accepted Answer

Electron < Proton < Neutron

Question 19

A student needs to prepare 250.0 mL of a 0.100 M $NaCl$ solution. How many grams of $NaCl$ are required? (Molar mass of $NaCl = 58.44 	ext{ g/mol}$)

Accepted Answer

1.46 g

Question 20

Which of the following best describes a limiting reactant in a chemical reaction?

Accepted Answer

The reactant that is completely consumed first, limiting the amount of product formed.

General Chemistry I: Exam 1 Study Guide

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