Q: A nutrition label states that a serving of food contains 10 g of fat, 5 g of protein, and 20 g of carbohydrates. Using the caloric values $$9\ \mathrm{kcal/g}$$ for fat and $$4\ \mathrm{kcal/g}$$ for both protein and carbohydrates, what is the total caloric content per serving?

$$(10 \times 9) + (5 \times 4) + (20 \times 4) = 90 + 20 + 80 = 190\ \mathrm{kcal}$$

Q: A sample contains $$3.0\ \mathrm{mol} of $$carbon atoms. How many atoms are present in the sample? (Avogadro's number $$= 6.02 \times 10$$^{23}$$\ \mathrm{atoms/mol})$$

$$3.0 \times 6.02 \times 10$$^{23}$$ = 1.81 \times 10$$^{24}$$\ \mathrm{atoms}$$

Question 1

Which of the following best defines 'kinetic energy' as it applies to chemistry?

Accepted Answer

The energy associated with the motion of particles.

Question 2

A sample of water is heated from $$25\ ^\circ\mathrm{C} to$$ $$75\ ^\circ\mathrm{C}. $$Which of the following best describes the type of change occurring?

Accepted Answer

A physical change, because only the temperature and kinetic energy of the molecules increase.

Question 3

Which of the following is a correct example of a heterogeneous mixture?

Accepted Answer

Oil and vinegar salad dressing

Question 4

Which of the following correctly lists the SI units for energy, mass, and temperature?

Accepted Answer

Joule, kilogram, Kelvin

Question 5

A nutrition label states that a serving of food contains 10 g of fat, 5 g of protein, and 20 g of carbohydrates. Using the caloric values $$9\ \mathrm{kcal/g}$$ for fat and $$4\ \mathrm{kcal/g}$$ for both protein and carbohydrates, what is the total caloric content per serving?

Accepted Answer

$$(10 	imes 9) + (5 	imes 4) + (20 	imes 4) = 90 + 20 + 80 = 190\ \mathrm{kcal}$$

Question 6

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 in a fixed ratio, while an element is a pure substance made of only one type of atom.

Question 7

Which of the following is the correct electron configuration for a neutral atom of sodium ($$Z = 11$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^1$$

Question 8

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 9

Which of the following elements is most likely to be chemically similar to sodium ($$Z = 11$$)?

Accepted Answer

Potassium ($$Z = 19)$$

Question 10

Which of the following best explains why atomic radius decreases across a period from left to right?

Accepted Answer

The number of protons increases, pulling electrons closer to the nucleus.

Question 11

A sample contains $$3.0\ \mathrm{mol} of $$carbon atoms. How many atoms are present in the sample? (Avogadro's number $$= 6.02 	imes 10$$^{23}$$\ \mathrm{atoms/mol})$$

Accepted Answer

$$3.0 	imes 6.02 	imes 10$$^{23}$$ = 1.81 	imes 10$$^{24}$$\ \mathrm{atoms}$$

Question 12

Which of the following best describes the trend in ionization energy as you move down a group in the periodic table?

Accepted Answer

Ionization energy decreases because the outer electrons are farther from the nucleus.

Question 13

Which of the following is the correct order of increasing electronegativity for the elements sodium (Na), chlorine (Cl), and oxygen (O)?

Accepted Answer

Na \u003c O \u003c Cl

Question 14

Which of the following best describes a chemical property?

Accepted Answer

Iron reacts with oxygen to form rust.

Question 15

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 16

A patient is given a 500 mg tablet of a medication. If the molar mass of the medication is $$250\ \mathrm{g/mol}$$, how many moles of the medication are in the tablet?

Accepted Answer

$$0.500\ \mathrm{g} \div 250\ \mathrm{g/mol} = 0.002\ \mathrm{mol}$$

Question 17

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a full valence shell of electrons, making them stable.

Question 18

Which of the following is the correct Lewis dot structure for carbon?

Accepted Answer

A 'C' symbol with four dots, one on each side.

Question 19

Which of the following best describes the difference between a physical and a chemical change?

Accepted Answer

A chemical change alters the composition of a substance, while a physical change does not.

Question 20

Which of the following best describes the relationship between heat ($$q$$), mass ($$m$$), specific heat ($$c$$), and temperature change ($$\Delta T) in $$the equation $$q = mc\Delta T$$?

Accepted Answer

The amount of heat absorbed or released is directly proportional to the mass, specific heat, and temperature change.

CHEM 1110 Exam 2 Study Guide: Matter, Energy, Atoms, and Elements

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