Subject: Bio - Chemistry

#17

Which of the following is not a pure substance?

A) Oxygen

B) Gold

C) Salt water

D) Carbon dioxide

Answer:   C

---

#18

What happens during oxidation?

A) Gain of electrons

B) Loss of electrons

C) Gain of protons

D) No electron change

Answer:   B

---

#19

Which pH value represents a neutral solution?

A) 0

B) 7

C) 14

D) 5

Answer:   B

---

#20

Which gas is most commonly involved in combustion reactions?

A) Nitrogen

B) Oxygen

C) Carbon dioxide

D) Hydrogen

Answer:   B

---

#21

Which of these is a base?

A) HCl

B) NaOH

C) CH3COOH

D) H2SO4

Answer:   B

---

#22

In a redox reaction, the substance that gains electrons is:

A) Oxidized

B) Reduced

C) Neutralized

D) Ionized

Answer:   B

---

#23

Which subatomic particle defines the atomic number?

A) Neutron

B) Proton

C) Electron

D) Nucleus

Answer:   B

---

#24

Which of the following is a heterogeneous mixture?

A) Air

B) Milk

C) Vinegar

D) Salad

Answer:   D

---

Page 3 of 30