Question 1

Which of the following statements best describes the difference between a law and a theory in chemistry?

Accepted Answer

A law is a summary of observed behavior, while a theory provides an explanation for that behavior.

Question 2

A student measures the mass of a sample three times and records the values: 2.51 g, 2.49 g, and 2.50 g. The true mass is 2.80 g. Which statement best describes the accuracy and precision of these measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following numbers has the correct number of significant figures for the result of the calculation $$4.56 	imes 1.4$$?

Accepted Answer

$$6.4 ($$two significant figures)

Question 4

Convert $$25.0$$ degrees Celsius to Kelvin. Use the formula $$K = ^\circ C + 273.15.$$

Accepted Answer

$$298.15\ K$$

Question 5

Which of the following is a heterogeneous mixture?

Accepted Answer

Salad with lettuce, tomatoes, and cucumbers

Question 6

A sample of gold has a mass of $$96.5\ g$$ and a volume of $$5.00\ cm^3$. What is the density of gold? Use the formula $$	ext{Density} = \frac{	ext{mass}}{	ext{volume}}$$.

Accepted Answer

$$19.3\ g/cm^3$

Question 7

Which of the following best describes an endothermic process?

Accepted Answer

A process in which the system absorbs heat from the surroundings

Question 8

A chemical reaction absorbs $$150.0\ J of $$heat and the temperature of $$10.0\ g of $$water increases by $$3.6\ ^\circ C. $$What is the specific heat capacity $$c of $$water in this experiment? Use $$q = mc\Delta T.$$

Accepted Answer

$$4.17\ J/g\cdot ^\circ C$$

Question 9

Which of the following is a physical change?

Accepted Answer

Melting of ice

Question 10

Which of the following statements about the conservation of mass is correct?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 11

Which of the following is an example of a compound?

Accepted Answer

Sodium chloride ($$NaCl)$$

Question 12

A student needs to convert $$5.00\ km to$$ $$m. $$Which of the following is the correct answer?

Accepted Answer

$$5000\ m$$

Question 13

Which of the following best describes a pure substance?

Accepted Answer

A material with a fixed composition and distinct properties

Question 14

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

Accepted Answer

$$3.45 	imes 10$$^{-4}$$

Question 15

A beaker contains $$100.0\ g of $$water at $$25.0\ ^\circ C. If$$ $$8360\ J of $$heat is added, what is the final temperature? (Specific heat of water $$c = 4.18\ J/g\cdot ^\circ C$$; use $$q = mc\Delta T.)$$

Accepted Answer

$$45.0\ ^\circ C$$

Question 16

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

Accepted Answer

A compound consists of two or more elements chemically combined, while an element is a pure substance made of only one kind of atom.

Question 17

Which of the following is a chemical property?

Accepted Answer

Reactivity with acid

Question 18

A thermometer reads $$21.6\ ^\circ C. $$What is this temperature in Fahrenheit? Use the formula $$^\circ F = \frac{9}{5}(^\circ C) + 32.$$

Accepted Answer

$$70.9\ ^\circ F$$

Question 19

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout

Question 20

A student is asked to determine the number of significant figures in the measurement $$0.00450 g. $$What is the correct answer?

Accepted Answer

3

Introduction to Chemistry: Quiz 1-3 Study Guide and Key Concepts

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