Q: Calculate the number of copper atoms in $$2.00$$ moles of copper. ($$N_A = 6.022 \times 10$$^{23}$$ atoms/mol)

$$1.20 \times 10$$^{24}$$ atoms

Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting in the presence of oxygen

Question 2

Which law states that matter is neither created nor destroyed in a chemical reaction?

Accepted Answer

Law of Conservation of Mass

Question 3

A student measures the mass of a sample three times and gets values very close to each other, but far from the actual mass. This demonstrates:

Accepted Answer

Low accuracy and high precision

Question 4

Which of the following is a derived SI unit?

Accepted Answer

Joule ($$J)$$

Question 5

A sample of water is decomposed into 16.0 g of oxygen and 2.0 g of hydrogen. What is the mass ratio of oxygen to hydrogen in water?

Accepted Answer

$$8:1$$

Question 6

Which statement about isotopes is correct?

Accepted Answer

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

Question 7

Which experiment led to the discovery of the electron?

Accepted Answer

Cathode ray tube experiment

Question 8

What is the charge and approximate mass of a neutron?

Accepted Answer

Charge: $$0$$, Mass: $$1$$ amu

Question 9

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation has more protons than electrons; an anion has more electrons than protons.

Question 10

Which of the following elements is most likely to react explosively with water?

Accepted Answer

Sodium ($$Na)$$

Question 11

Calculate the number of copper atoms in $$2.00$$ moles of copper. ($$N_A = 6.022 	imes 10$$^{23}$$ atoms/mol)

Accepted Answer

$$1.20 	imes 10$$^{24}$$ atoms

Question 12

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

Accepted Answer

Elements are arranged in order of increasing atomic number.

Question 13

A student needs to convert $$25.0$$ inches to centimeters. Given $$1$$ inch $$= 2.54 cm$$, what is the correct answer with the proper number of significant figures?

Accepted Answer

$$63.5 cm$$

Question 14

Which of the following is a physical property?

Accepted Answer

Melting point

Question 15

Which of the following best explains why gasoline is a good fuel?

Accepted Answer

It has a high potential energy in its chemical bonds.

Question 16

A sample contains $$3.0 	imes 10$$^{24}$$ atoms of aluminum. How many moles of aluminum are present? (N_A = 6.022$$ 	imes $$10^{23}$$ atoms/mol)

Accepted Answer

$$4.98$$ mol$

Question 17

Which of the following is the correct symbol for an isotope of neon with 10 protons and 12 neutrons?

Accepted Answer

$$^{22}_{10}Ne$$

Question 18

Which of the following best describes the Law of Multiple Proportions?

Accepted Answer

When two elements form more than one compound, the masses of one element that combine with a fixed mass of the other are in ratios of small whole numbers.

Question 19

Which of the following is a correct statement about noble gases?

Accepted Answer

They are very unreactive.

Question 20

A student multiplies $$2.17 cm by$$ $$4.2 cm. $$What is the correct answer with the proper number of significant figures?

Accepted Answer

$$9.1 cm$^2$$

Measurement, Physical and Chemical Change, and Atomic Theory: General Chemistry Study Notes

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