Chemistry Year 10

Question 1

Physical change

Answer 1

No new substance made
Reversible
Change in state
No fizzing or bubbling
No colour change

Question 2

Chemical change

Answer 2

Energy change
Non reversible
New substance made
Precipitate formed
Fizzing or bubbling
Colour change

Question 3

Universal indicator

Answer 3

ACID = red or orange
BASE = blue or purple
NEUTRAL = green

Question 4

pH scale

Answer 4

1-6 = ACID
1= strong acid, 6= weak

7= NEUTRAL

8-14 = BASE
8 = weak
14 = strong base

Question 5

Discuss OH-

Answer 5

Hydroxide ions, a BASE.
OH- ions released when put in water
Remove the H+ ions from a substance

Question 6

Discuss H+ ions

Answer 6

Hydrogen ions
Are an ACID
H+ ions released when put in water

Question 7

Properties of acids

Answer 7

Turn blue litmus paper red
Have a sour taste
Produce hydrogen when mixed with a metal
Produce CO2 when mixed with carbonate (marble chips)

Question 8

Organic acid

Answer 8

Usually weak
Are found in nature
Contain carbon

Question 9

Mineral acid

Answer 9

Usually strong (eg hydrochloride acid HCl)

Question 10

Acid + base =

Answer 10

Water + salt

Question 11

Acid + metal =

Answer 11

Hydrogen + salt

Question 12

Acid + carbonate =

Answer 12

Water + salt + carbon dioxide (CO2)

Question 13

Metal + oxygen =

Answer 13

Metal oxide

Question 14

Metal + water =

Answer 14

Metal hydroxide + hydrogen

Question 15

HCl + KOH/

Hydrochloric acid + potassium hydroxide =

Answer 15

H2O + KCl/

Water + potassium chloride

Question 16

H2SO4 + CuCo3/

Sulfuric acid + copper carbonate =

Answer 16

H2O + CO2 + CuSO4/

Water + carbon dioxide + copper sulphate

Question 17

HNO3 + Mg/

Nitric acid + magnesium =

Answer 17

H2O + MgNO3/

Water + magnesium nitrate

Question 18

Testing for HYDROGEN

Answer 18

Hydrochloric acid (HCl) and magnesium (Mg) together makes hydrogen. To test for H2, light a match near the top of the test tube and it will make a pop noise

Question 19

Testing for Carbon Dioxide

Answer 19

Hydrochloride acid (HCl) and marble chips (ClCO3) together make carbon dioxide (CO2). Bubble it throu lime water & if it turns milky it is CO2.

Question 20

What is O+ ?

Answer 20

Oxide

Question 21

What is OH-?

Answer 21

Hydroxide

Question 22

What is SO4 ?

Answer 22

Sulphate

Question 23

What is CO3 ?

Answer 23

Carbonate

Question 24

What is NO3 ?

Answer 24

Nitrate

Question 25

How and why do atoms and molecules form ions?

Answer 25

Because they do not have a full outer shell. They will either lose or gain electrons to make a full outer shell. That means they will turn positive or negative. If they lose electrons, they become positive If they gain electrons, they become positive

Question 26

Household acids

Answer 26

``` Vinegar Tartaric acid Citric acid Tomato juice Orange juice Fizzy drink ```

Question 27

Household bases

Answer 27

Bases have a soapy feel, so any cleaning product is normally a base Eg handy Andy, janola ``` Nail polish remover Oven cleaner Bleach Toothpaste Detergent Shampoo ```

Question 28

List some metals from MOST reactive to LEAST reactive

Answer 28

{MOST REACTIVE }. Ca -> Mg -> Al -> Zn -> Fe -> Cu -> Au {LEAST REACTIVE } Calcium -> magnesium -> aluminium -> zinc -> iron -> copper -> gold

Question 29

Discuss SHERBET

Answer 29

Sherbet contains an acid (citric acid) & a carbonate (NaHCO3). When combined, these make carbon dioxide (CO2), which creates the frothing in the mouth. The other acid on its own (tartaric acid) creates the sour taste and the icing sugar causes the sweet taste. Your tongue becomes wet because the acid and the carbonate (citric acid and baking soda) together, also make water (H2O). The salty aftertaste is also because the acid and carbonate together also make a salt.

Question 30

What is the COLLISION THEORY?

Answer 30

Rates of reaction are directly proportional to the amount of collisions between atoms in a reaction.

Question 31

Name three ways the rate of collision (reaction) may be increased. (Nb Collision Theory = rates of reaction are directly proportional to the amount of collisions between atoms in a reaction).

Answer 31

1. INCREASE TEMPERATURE. The atoms speed up and therefore more likely to collide with other atoms. They have more energy. 2. INCREASE CONCENTRATION. There are more atoms, so more collisions. 3. INCREASE SURFACE AREA. There are more atoms available for collisions.

Question 32

Discuss NEUTRALISATION.

Answer 32

BASES have the opposite properties to ACIDS. BASES remove ACID particles from a solution. A BASE is called an ALKALI if it can be dissolved in water. The resulting solution is ALKALINE. All alkaline solutions have pH higher than 7. BASES can neutralize ACIDIC solutions by removing the H+ ions (acidic particles). When a base dissolves in water, it releases hydroxide ions (OH-). These combine with the free H+ ions to make water (H2O) with a pH equal to 7.