Simple Chemical Reactions

Question 1

what are the three ways to know if a chemical reaction has taken place

Answer 1

1. Formation of a new substance
2. Change in appearance
3. Detectable energy change

Question 2

substances that react together in the equation are called

Answer 2

the reactants

Question 3

the substances formed after a chemical reaction took place are called

Answer 3

products

Question 4

identify the product : potassium hydroxide reacts with nitric acid to give potassium nitrate and water

Answer 4

potassium nitrate and water

Question 5

identify the reactant: lithium hydroxide and hydrogen are formed when lithium is added to a beaker containing water

Answer 5

lithium and water

Question 6

identify the product: lithium + sulfuric acid –> lithium sulfate + hydrogen

Answer 6

lithium sulfate and hydrogen

Question 7

identify the reactants: magnesium + oxygen –> magnesium oxide

Answer 7

magnesium, oxygen

Question 8

word equation:

Answer 8

reactants –> products

Question 9

a reaction happens when

Answer 9

two or more particles interact, the bonds holding the reactants break, the atoms rearrange and new bonds are formed between them, a new substance is formed

Question 10

the mass in a chemical reaction is…

Answer 10

conserved. No atoms are created or destroyed

Question 11

what is required to break bonds

Answer 11

energy in the form of heat

Question 12

how can you test for a gas formed in a chemical reaction

Answer 12

pop test- use a lit splint near the mouth of a test tube containing the gas. If a pop sound is heard when it means that it contains hydrogen. Hydrogen reacts with oxygen. Some water droplets are also seen on the side of the test tube

Question 13

reactive metals…

Answer 13

take easily part in chemical reactions

Question 14

unreactive metals…

Answer 14

do not take easily part in chemical reactions

Question 15

reactivity is

Answer 15

a measure of how readily a substance will react with another

Question 16

the most reactive metal is

Answer 16

potassium

Question 17

reaction of metal and water

Answer 17

metal + water –> metal hydroxide + hydrogen

Question 18

when potassium reacts with water…

Answer 18

• it moves quickly on the surface of the water
• a hissing sound can be heard because of the production of oxygen
• hydrogen burns giving a purple flame
• the metal disappears

Question 19

word equation for reaction of potassium with water

Answer 19

potassium + water –> potassium hydroxide + hydrogen

Question 20

lithium + water –>

Answer 20

lithium hydroxide + hydrogen

Question 21

reaction of metal with acids

Answer 21

metal + acid –> metal salt + hydrogen

Question 22

salts for acids

Answer 22

hydrochloric acid: metal chloride
sulfuric acid: metal sulfate
nitric acid: metal nitrate

Question 23

sodium + hydrochloric acid –>

Answer 23

sodium chloride + hydrogen

Question 24

lithium + sulfuric acid –>

Answer 24

lithium sulfate + hydrogen

Question 25

magnesium + nitric acid –>

Answer 25

magnesium nitrate + hydrogen

Question 26

if a metal is below hydrogen in the reactivity series…

Answer 26

it won’t react with acid to give salt and hydrogen

Question 27

combustion is

Answer 27

the reaction (burning) of a substance with oxygen to produce heat and light energy

Question 28

metals react with oxygen in the air to produce…

Answer 28

metal oxides

Question 29

magnesium + oxygen

Answer 29

magnesium oxide

Question 30

non metal + oxygen

Answer 30

non metal oxide

Question 31

carbon + oxygen

Answer 31

carbon dioxide

Question 32

test for carbon dioxide

Answer 32

we blow inside clear limewater which turns cloudy once the gas is bubbled through

Question 33

when magnesium is burned in the air we can see a…

Answer 33

white flame