oxides, salts, anions

Question 1

name the 4 types of oxides

Answer 1

basic, acidic, neutral, amphoteric

Question 2

what is the difference between basic and acidic oxides?

Answer 2

basic oxides are formed from metals and react with acids to form salt and water
acidic oxides are formed from non-metals and dissolve in water to form oxides

Question 3

what type of oxide is aluminium oxide?

Answer 3

amphoteric

Question 4

what type of oxide is zinc oxide?

Answer 4

amphoteric

Question 5

name 2 neutral oxides

Answer 5

carbon monoxide, nitrous oxide

Question 6

describe the reaction of oxygen and magnesium

Answer 6

basic. a magnesium ribbon is lit over a bunsen burner then plunged into a jar of oxygen. bright white flame and leaves behind white ash

Question 7

describe the reaction of oxygen and iron wool

Answer 7

basic. hot iron wool plunged into jar of oxygen. there is a shower of orange sparks and a black solid iron(III) oxide remains

Question 8

describe the reaction of oxygen and copper

Answer 8

basic. copper is too unreactive. heated in oxygen, surface turns black copper(II) oxide

Question 9

describe the reaction of oxygen and carbon

Answer 9

acidic. powdered carbon is heated over a bunsen burner until red hot. then plunged into oxygen jar. glows bright red. forms carbon dioxide

Question 10

describe the reaction of oxygen and sulfur

Answer 10

acidic. sulfur catches fire over a bunsen burner with a blue flame. forms sulfur dioxide

Question 11

describe the reaction of oxygen and phosphorous

Answer 11

acidic. catches alight in the air. forms white solid phosphorous(V) oxide

Question 12

define ‘salt’

Answer 12

a compound made of a positive and negative ion

Question 13

how are ammonium salts made?

Answer 13

reacting ammonia with an acid

Question 14

what are all the soluble salts?

Answer 14

1. sodium, potassium, ammonium salts
2. nitrates
3. chlorides except silver chloride and lead chloride
4. all sulphates except barium sulphate, lead sulphate

Question 15

what are all the insoluble salts?

Answer 15

1. all carbonates except sodiu, potassium, ammonium

2. all oxides and hydroxides except SAP

Question 16

what 3 reactions produce salts?

Answer 16

acid + metal → salt + hydrogen
acid + alkali → salt + water
acid + carbonate → salt + water + carbon dioxide

Question 17

when is precipitation used?

Answer 17

using 2 soluble salts to produce a third insoluble one

Question 18

when is the carbonate method used?

Answer 18

soluble acid + insoluble base → soluble salt

Question 19

when is titration used?

Answer 19

soluble acid + soluble base → soluble salt

Question 20

explain the titration method step-by-step using sodium hydroxide

Answer 20

1. add sodium hydroxide into a flask using a pipette and two drops phenolphthalein
2. add the acid from a burette and swirl
3. the indicator turns colourless
4. look at how much acid was used
5. repeat without the indicator
6. heat the solution over a BB

Question 21

how do you test an anion as a gas?

Answer 21

begin with the solid salt or aqueous solution

Question 22

how do you test an anion as a precipitate?

Answer 22

start with the aqueous solution

Question 23

name the halide ions and how to test them

Answer 23

Cl-, Br-, I-

1. to a small amount of solution add equal volume dilute nitric acid then add silver nitrate (aq)
2. silver halides are insoluble so a precipitate will form

white: chloride
cream: bromide
yellow: iodide

Question 24

what is the chemical formula for sulfate?

Answer 24

(SO4)2-

Question 25

how do you test for sulfate ions?

Answer 25

1. to a small amount of solution add equal volume dilute hydrochloric acid then add barium nitrate solution
2. barium sulfate is insoluble. forms a white precipitate

Question 26

what is the chemical formula for sulfite?

Answer 26

SO3 2-

Question 27

how do you test for sulfite?

Answer 27

1. to a small amount of solution add equal volume dilute hydrochloric acid
2. heat. sulfur dioxide is given off
3. soak a small piece of paper in potassium manganate(VII) and place it at the mouth of the test tube. it turns colourless.

Question 28

how do you test for nitrate ions?

Answer 28

1. to a small amount of solution or solid, add a little dilute sodium hydroxide then add small pieces of aluminium foil
2. heat gently
3. if ammonia gas is given off, nitrates are present

Question 29

write the equation for nitrate and sodium hydroxide

Answer 29

8Al+3NO3+5OH+2H2O→3NH3+8AlO2

Question 30

how do you test for carbonate ions?

Answer 30

1. to a small amount of solution or solid, add a little dilute hydrochloric acid
2. if the gas that bubbles off turns limewater milky, present