Question 1

Which of the following is the correct way to express the number 0.000456 in scientific notation?

Accepted Answer

$$4.56 	imes 10$$^{-4}$$

Question 2

A student measures the mass of a sample as 12.30 g and its volume as 4.5 mL. What is the density of the sample, reported to the correct number of significant figures?

Accepted Answer

$$2.7\ \mathrm{g/mL}$$

Question 3

Which of the following statements best describes the difference between intensive and extensive properties?

Accepted Answer

Intensive properties do not depend on the amount of substance, while extensive properties do.

Question 4

Which of the following is an example of a systematic error in a laboratory experiment?

Accepted Answer

A balance that always reads 0.05 g too high.

Question 5

How many significant figures are in the measurement 0.004560?

Accepted Answer

4

Question 6

A temperature is recorded as 25.0 $$^{\circ}C. $$What is this temperature in Kelvin?

Accepted Answer

$$298.2\ \mathrm{K}$$

Question 7

Which of the following best defines the law of conservation of energy?

Accepted Answer

Energy cannot be created or destroyed, only converted from one form to another.

Question 8

Convert 5.00 miles to kilometers. (1 mile = 1.609 km)

Accepted Answer

$$8.05\ \mathrm{km}$$

Question 9

Which of the following is an exact number?

Accepted Answer

The number of students in a classroom.

Question 10

A reaction releases 150 J of heat and does 50 J of work on the surroundings. What is the change in internal energy ($$\Delta E) of $$the system?

Accepted Answer

$$-200\ \mathrm{J}$$

Question 11

Which of the following conversions involves both a change in prefix and a change in unit type?

Accepted Answer

Converting 1.0 kg to 2.20 lb

Question 12

A student needs to prepare 250.0 mL of a solution. Which measurement is most precise?

Accepted Answer

Using a 250.0 mL volumetric flask.

Question 13

Which of the following best describes potential energy?

Accepted Answer

Energy stored due to an object's position or composition.

Question 14

A sample of gold has a mass of 19.3 g and a volume of 1.00 cm$$^3. $$What is the density of gold?

Accepted Answer

$$19.3\ \mathrm{g/cm}^3$$

Question 15

Which of the following is a correct statement about random error?

Accepted Answer

Random error causes measurements to be scattered around the true value.

Question 16

A measurement is recorded as 0.02030 g. How many significant figures does it have?

Accepted Answer

4

Question 17

Which of the following best describes kinetic energy?

Accepted Answer

Energy due to motion.

Question 18

A student converts 2.50 hours to seconds. What is the correct answer?

Accepted Answer

$$9,000\ \mathrm{s}$$

Question 19

Which of the following is NOT a correct SI base unit?

Accepted Answer

Liter (L)

Question 20

A calculation involves multiplying 3.00 (2 significant figures) by 2.0 (2 significant figures) and dividing by 1.00 (3 significant figures). How many significant figures should the final answer have?

Accepted Answer

2

General Chemistry - chapter E

Guida di studio - Domande di pratica

Study guide - Flashcard