Chemistry Fundamentals

Question 1

What is white light composed of?

Accepted Answer

All colors of visible light

Question 2

Why do different elements emit different colors in a flame test?

Accepted Answer

Because of different electron configurations and energy level jumps

Question 3

A 9 g sample of Al reacts with O₂ to form 17 g of Al₂O₃. What mass of O₂ was used?

Accepted Answer

8 g

Question 4

What is the empirical formula of C₆H₁₂O₆?

Accepted Answer

CH₂O

Question 5

Which of the following elements is a noble gas?

Accepted Answer

Argon

Question 6

What is the balanced form of this equation: Fe + O₂ → Fe₂O₃?

Accepted Answer

4 Fe + 3 O₂ → 2 Fe₂O₃

Question 7

Which of the following is an example of a mixture?

Accepted Answer

Air

Question 8

What is the molar mass of CaCO_3? (Ca=40, C=12, O=16)

Accepted Answer

88 g/mol

Question 9

Which subatomic particle has a negative charge?

Accepted Answer

Electron

Question 10

What type of change is rust forming on iron?

Accepted Answer

Chemical

Question 11

What type of light has the shortest wavelength in the visible spectrum?

Accepted Answer

violet

Question 12

A compound is 40% C, 6.7% H, and 53.3% O. What is its empirical formula?

Accepted Answer

CH₂O

Question 13

Which unit is used to express molar mass?

Accepted Answer

g/mol

Question 14

Which of the following is always conserved in a chemical reaction?

Accepted Answer

Mass

Question 15

How many molecules are in 0.75 mol of CO₂?

Accepted Answer

4.52 × 10²³

Question 16

What is the molar mass of H_2O? (H=1, O=16)

Accepted Answer

18 g/mol

Question 17

How many moles are in 36 g of H_2O? (H=1, O=16)

Accepted Answer

3.0 mol

Question 18

What is the mass of 4.5 moles of O_2 gas? (O=16)

Accepted Answer

160 g

Question 19

What is the hydrogen to oxygen ratio in H₂O₂?

Accepted Answer

1:1

Question 20

Which of the following best represents a compound?

Accepted Answer

H₂O

Question 21

What is the percent composition of H in H₂O?

Accepted Answer

11.1

Question 22

According to Bohr’s model, what happens when an electron falls from a higher to a lower energy level?

Accepted Answer

It releases energy as light

Question 23

What is the number of protons in an atom of nitrogen (atomic number 7)?

Accepted Answer

7

Question 24

Which of the following particles is found in the nucleus of an atom?

Accepted Answer

Proton and neutron

Question 25

What is Avogadro’s number?

Accepted Answer

6.022 × 10²³

Chemistry Fundamentals

Questions 25

Chemistry Fundamentals

Questions 25