Acids, Base and salts

Question 1

what is an acid

Answer 1

a proton donor

Question 2

what is a base

Answer 2

a proton acceptor

Question 3

acidic oxide

Answer 3

an oxide that reacts with a base to form a salt and water

Question 4

basic oxide

Answer 4

an oxide that reacts with an acid to form a salt and water

Question 5

bases

Answer 5

substances that can react with acids and neutralise them to make a salt and water are called bases. They are usually metal oxides or metal hydroxides. For example, copper oxide and sodium hydroxide are bases.

Question 6

what does acid and metal form

Answer 6

salt and hydrogen

Question 7

what does acid and oxides form

Answer 7

salt and water

Question 8

what does acid and carbonate form

Answer 8

salt and water and CO2

Question 9

what does acid and alkalis form

Answer 9

salt and water

Question 10

why is it important for to control acidity in the environment

Answer 10

plants like to grow where the PH is 7 so making the soil acidic can prevent them from growing.

acid can leak into rivers and lakes from factories which can damage ecosystems

Question 11

classify oxides as either acidic or basic, related to metallic and non-metallic character of the other element

Answer 11

in general, metals react with oxygen in order to form basic oxides
in general, non-metals react with oxygen in order to form acidic oxides

Question 12

test for ammonium

Answer 12

add a little dilute hydroxide solution and heat gently
if ammonia gas is given off, ammonium ions were present in the solution.
(Ammonia gas turns red litmus blue and has a sharp smell)

Question 13

test for copper (ii), iron (ii), iron (iii) and zinc

Answer 13

add a few drops of dilute sodium hydroxide solution.
pale blue precipitate indicates copper (ii)
green precipitates iron (ii)
red-brown precipitate indicates iron (iii)
add more sodium hydroxide and ammonium hydroxide
if the precipitate dissolves, zinc is present

Question 14

test for carbonate ions

Answer 14

add a little dilute hydroxide acid

if mixture bubbles and gives off gas, that turns limewater milky, carbonate ions were present

Question 15

test for chloride ions

Answer 15

add an equal volume of dilute nitric acid
add silver nitrate solution
white precipitate indicates chloride ions

Question 16

test for nitrate

Answer 16

add a little sodium hydroxide solution.
add some aluminium foil. Heat gently
if ammonia gas is given off, the unknown substance contains nitrate ions

Question 17

test for sulfate

Answer 17

add an equal volume of dilute HCL.
then add barium nitrate solution
barium nitrate is insoluble, so if sulfate ions are present a white precipitate will form

Question 18

test for ammonia (gas)

Answer 18

ammonia gas has a strong sharp smell and turns red litmus blue

Question 19

test for CO2

Answer 19

turns limewater milky

Question 20

test for chlorine

Answer 20

turns indicator paper white

Question 21

test for Hydrogen

Answer 21

collect the gas in a tube and hold a lighted splint to it.

the gas burns with a squeaky pop

Question 22

test for oxygen.

Answer 22

collect the gas in a tube and hold a glowing splint to it.

the splint will relight.

Question 23

how to make salt

Answer 23

metal oxide, metal, metal hydroxide. the second part comes from acid