Chemistry EOY 9

Question 1

What are the charges and relative masses of protons, neutrons, and electrons?

Answer 1

Proton: +1 charge, 1 mass | Neutron: 0 charge, 1 mass | Electron: -1 charge, very small mass (≈ 0)

Question 2

How do you calculate the number of protons, neutrons, and electrons in an atom?

Answer 2

Protons = atomic number | Electrons = atomic number | Neutrons = mass number - atomic number

Question 3

How are electrons arranged around the nucleus?

Answer 3

In energy levels (shells): 1st shell = max 2 electrons, 2nd = max 8, 3rd = max 8, etc.

Question 4

What is the relative atomic mass (Ar)?

Answer 4

The average mass of all isotopes of an element, weighted by their abundance.

Question 5

How do you calculate relative atomic mass?

Answer 5

Ar = (isotope1 × %abundance1 + isotope2 × %abundance2) ÷ 100

Question 6

An atom has 11 protons, 12 neutrons, and 11 electrons. What is its atomic number, mass number, and charge?

Answer 6

Atomic number = 11, Mass number = 23, Charge = 0 (same protons and electrons)

Question 7

What are the products of metal + acid?

Answer 7

Salt + hydrogen gas

Question 8

What are the products of metal carbonate + acid?

Answer 8

Salt + carbon dioxide + water

Question 9

What are the products of metal oxide + acid?

Answer 9

Salt + water

Question 10

What are the products of fuel + oxygen (combustion)?

Answer 10

Carbon dioxide + water (if complete combustion)

Question 11

How do you name salts?

Answer 11

Metal gives the first part (e.g. sodium), acid gives the second part: Hydrochloric acid → chloride, Sulfuric acid → sulfate, Nitric acid → nitrate

Question 12

What is the name of the salt formed from sodium + hydrochloric acid?

Answer 12

Sodium chloride

Question 13

What is the formula of magnesium sulfate?

Answer 13

MgSO₄

Question 14

How do you write the formula for copper(II) nitrate?

Answer 14

Cu(NO₃)₂

Question 15

What is the balanced equation for magnesium + hydrochloric acid → magnesium chloride + hydrogen?

Answer 15

Mg + 2HCl → MgCl₂ + H₂

Question 16

Predict the products of calcium carbonate + nitric acid.

Answer 16

Calcium nitrate + carbon dioxide + water

Question 17

Balance the equation: H₂ + O₂ → H₂O

Answer 17

2H₂ + O₂ → 2H₂O

Question 18

What is an exothermic reaction?

Answer 18

A reaction that gives out heat to the surroundings (temperature increases)

Question 19

What is an endothermic reaction?

Answer 19

A reaction that takes in heat from the surroundings (temperature decreases)

Question 20

Is combustion exothermic or endothermic?

Answer 20

Exothermic

Question 21

Is photosynthesis exothermic or endothermic?

Answer 21

Endothermic

Question 22

The temperature rose during a reaction. What type of reaction was it?

Answer 22

Exothermic

Question 23

What are the 4 main factors that increase the rate of reaction?

Answer 23

1. Higher temperature 2. Higher concentration (of reactants) 3. Larger surface area (e.g. powder) 4. Use of a catalyst

Question 24

How does increasing temperature affect reaction rate?

Answer 24

Particles move faster → more frequent & energetic collisions

Question 25

Why does a powder react faster than a lump?

Answer 25

Greater surface area = more collisions

Question 26

What is a catalyst?

Answer 26

A substance that speeds up a reaction without being used up

Question 27

A powdered reactant reacts faster than a lump. Why?

Answer 27

It has a larger surface area for collisions