Q: A student measures the mass of a sample as 12.30 g and its volume as 4.10 mL. What is the density of the sample?

$$\frac{12.30}{4.10} = 3.00\ \text{g/mL}$$

Q: Convert 2.5 kg to grams.

$$2.5 \times 1000 = 2500\ \text{g}$$

Q: A patient’s temperature rises from 37.0°C to 39.5°C. What is the change in temperature in Kelvin?

$$39.5 - 37.0 = 2.5\ ^\circ\text{C}$$, so $$2.5\ \text{K}$$

Q: What is the specific heat equation used to calculate the heat required to raise the temperature of a substance?

$$q = m \times c \times \Delta T$$

Q: A sample contains 3.0 moles of sodium atoms. How many atoms are present?

$$3.0 \times 6.022 \times 10$$^{23}$$ = 1.81 \times 10$$^{24}$$ atoms

Q: A solution is prepared by dissolving 5.0 g of NaCl in enough water to make 250 mL of solution. What is the concentration in g/mL?

$$\frac{5.0}{250} = 0.020\ \text{g/mL}$$

Question 1

Which of the following statements best describes a chemical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

A student measures the mass of a sample as 12.30 g and its volume as 4.10 mL. What is the density of the sample?

Accepted Answer

$$\frac{12.30}{4.10} = 3.00\ 	ext{g/mL}$$

Question 3

Which of the following is NOT a step in the scientific method?

Accepted Answer

Accepting results without question

Question 4

How many significant figures are in the measurement 0.00450 mL?

Accepted Answer

3

Question 5

Convert 2.5 kg to grams.

Accepted Answer

$$2.5 	imes 1000 = 2500\ 	ext{g}$$

Question 6

A patient’s temperature rises from 37.0°C to 39.5°C. What is the change in temperature in Kelvin?

Accepted Answer

$$39.5 - 37.0 = 2.5\ ^\circ	ext{C}$$, so $$2.5\ 	ext{K}$$

Question 7

Which of the following is a pure substance?

Accepted Answer

Salt (NaCl)

Question 8

Calculate the number of protons in an atom of chlorine ($$^{35}_{17}	ext{Cl}).$$

Accepted Answer

17

Question 9

Which element is in period 2 and group 1 of the periodic table?

Accepted Answer

Lithium

Question 10

A radioactive isotope has a half-life of 10 years. If you start with 80 g, how much remains after 30 years?

Accepted Answer

10 g

Question 11

Which of the following best describes the difference between mass number and atomic number?

Accepted Answer

Mass number is the sum of protons and neutrons; atomic number is the number of protons.

Question 12

Which process is an example of a physical change?

Accepted Answer

Boiling water

Question 13

What is the specific heat equation used to calculate the heat required to raise the temperature of a substance?

Accepted Answer

$$q = m 	imes c 	imes \Delta T$$

Question 14

Which of the following is a heterogeneous mixture?

Accepted Answer

Sand and iron filings

Question 15

A sample contains 3.0 moles of sodium atoms. How many atoms are present?

Accepted Answer

$$3.0 	imes 6.022 	imes 10$$^{23}$$ = 1.81 	imes 10$$^{24}$$ atoms

Question 16

Which of the following is the correct electron configuration for a neutral atom of oxygen?

Accepted Answer

1s$$^2 2s$^2 2p$^4$$

Question 17

Which of the following particles has the greatest penetrating power?

Accepted Answer

Gamma ray

Question 18

A solution is prepared by dissolving 5.0 g of NaCl in enough water to make 250 mL of solution. What is the concentration in g/mL?

Accepted Answer

$$\frac{5.0}{250} = 0.020\ 	ext{g/mL}$$

Question 19

Which of the following best explains why water has a high specific heat?

Accepted Answer

Water molecules form strong hydrogen bonds that require more energy to break.

Question 20

Which of the following changes of state is exothermic?

Accepted Answer

Freezing

Review Sheet: Exam 1 (Chapters 1-5) – GOB Chemistry Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard