$$217.1 \times 4.20 = 911.82 cm$^2$$, rounded to $$912 cm$^2 (3 $$significant figures)

$$6.022 \times 10$$^{23}$$ molecules/mol

$$2.45 \times 6.022 \times 10$$^{23}$$ = 1.48 \times 10$$^{24}$$ atoms

Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting when exposed to oxygen, forming iron(III) oxide.

Question 2

Which statement about physical and chemical changes is correct?

Accepted Answer

Physical changes can be reversed without changing the chemical identity of the substance.

Question 3

Which of the following is an example of kinetic energy?

Accepted Answer

Movement of atoms in a heated gas.

Question 4

According to the law of conservation of energy, which statement is true?

Accepted Answer

Energy is transferred from one form to another, but the total amount remains constant.

Question 5

Which SI unit is used to measure the amount of substance?

Accepted Answer

mol

Question 6

A student measures the mass of a sample as 0.0540 g. How many significant figures are in this measurement?

Accepted Answer

4

Question 7

Which of the following numbers has three significant figures?

Accepted Answer

408

Question 8

If you multiply 217.1 cm by 4.20 cm, which answer is correctly rounded for significant figures?

Accepted Answer

$$217.1 	imes 4.20 = 911.82 cm$^2$$, rounded to $$912 cm$^2 (3 $$significant figures)

Question 9

Which statement about Dalton’s atomic theory is correct?

Accepted Answer

Atoms of a given element have the same mass and properties.

Question 10

Which experiment led to the discovery of the electron?

Accepted Answer

Thomson’s cathode ray tube experiment.

Question 11

What is the charge of a proton?

Accepted Answer

$$+1.60 	imes 10$$^{-19}$$ C

Question 12

Which of the following best describes an isotope?

Accepted Answer

Atoms with the same atomic number but different numbers of neutrons.

Question 13

A neutral atom of sodium ($$^{23}_{11}Na) $$has how many electrons?

Accepted Answer

11

Question 14

Which of the following elements is most likely to form a cation?

Accepted Answer

Sodium

Question 15

What is Avogadro’s number?

Accepted Answer

$$6.022 	imes 10$$^{23}$$ molecules/mol

Question 16

Calculate the number of copper atoms in 2.45 mol of copper.

Accepted Answer

$$2.45 	imes 6.022 	imes 10$$^{23}$$ = 1.48 	imes 10$$^{24}$$ atoms

Question 17

Which law states that all samples of a given compound have the same proportions of their constituent elements?

Accepted Answer

Law of Definite Proportions

Question 18

Which group of elements on the periodic table is most likely to react explosively with water?

Accepted Answer

Alkali metals

Question 19

Which of the following is a derived SI unit?

Accepted Answer

Meter per second squared ($$m/s^2)$$

Question 20

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

Accepted Answer

$$16.0/2.0 = 8:1$$

Chapter 1: Measurement, Physical and Chemical Change – General Chemistry Study Notes

스터디 가이드 - 연습 문제