Alkalines and acids

Question 1

alkalines are __ bases

Answer 1

bases which are soluble in water

Question 2

acids form __ ions when in water

Answer 2

H+ as the only positive ion

Question 3

bases are __ or __

Answer 3

metal oxides or metal hydroxides

Question 4

photosynthesis is chemical/physical change

Answer 4

chemical
new substance is produced

Question 5

boiling water is chemical or physical change

Answer 5

physical
no new substance was formed

Question 6

digestion of food and cooking an egg is chemical or physical change

Answer 6

chemical because new substance is produced (protein and breaking down into different substances)

Question 7

physical change (substance)

Answer 7

no new substance is formed

Question 8

physical change (reversible)

Answer 8

are mostly reversible

Question 9

physical change (chemical compostition)

Answer 9

only change in physical properties, not its chemical composition

Question 10

chemical change (reversibie)

Answer 10

are difficult or impossible to reverse

Question 11

chemical change (substance)

Answer 11

new substance is formed

Question 12

chemical change has chemical composition changed. T/F?

Answer 12

t

Question 13

reactants are

Answer 13

substances at first beofre a chemical change

Question 14

chemical change is a result of

Answer 14

a chemical reaction

Question 15

Types of chemical changes

Answer 15

mixing 2 substances together (react when mixed at room temp w/o need for heating)
oxygen (result in chemical changes)
heat (when heat is applied)
light (absorption)

Question 16

chemical reaction: how to stabilise

Answer 16

stabilise charges and ensure that both sides have the same amount of ions of the same type. If unequal, add in numbers in front

Question 17

chemical reactions are to be written with chemical symbols without

Answer 17

charges

Question 18

mixing 2 or more substances
example of this chemical change?

Answer 18

neutralisation (acid will react with the base to form salt and water)

Question 19

heat
example?

Answer 19

thermal decomposition
(a substance is broken down into two or more simpler substances due to the effect of heat)

cooking (denatured by heat and change colour and texture)

Question 20

oxygen
examples of this chemical change

Answer 20

rusting (metals rust in the presence of water and oxygen). Rust produced is a reddish brown oxide of iron

combustion (combination of a substance with oxygen in presence of heat)

cellular respiration (take in oxygen to release energy stored in glucose

Question 21

light
initiation by absorption of energy in the form of light
examples?

Answer 21

photosynthesis

Question 22

photosynthesis chemical formula

Answer 22

carbon dioxide plus water —- glucose + oxygen

Question 23

cellular respiration chemical formula

Answer 23

glucose + oxygen—
carbon dioxide + water

Question 24

some substances react when an electrical charge is applied
examples?

Answer 24

Electrolysis
-chemical decomposition
water is broken down into hydrogen and oxygen

Electroplating
-process in which a substance is coated with a metal with a passage of electric current
(can stop rusting, to make jewellery more attractive

Question 25

Definition of acid

Answer 25

A substance that produces H+ ions as the only positive ion (the only ion that has positive charge as a result of a chemical reaction)

Question 26

Common acids

Answer 26

Hydrochloric acid (HCl) Nitric acid (HNO3) Sulfuric acid (H2SO4) All have H, hydrogen

Question 27

(aq) means

Answer 27

The substance has dissolved in water

Question 28

Three main reactions involving acids

Answer 28

Metal and acid Base and acid Carbonate and acid

Question 29

acids react with __ metals. equation for this chemical reaction?

Answer 29

most (copper, gold and silver are unreactive) acid + reactive metal= salt + hydrogen gas

Question 30

test for hydrogen gas

Answer 30

using a burning splint, hydrogen gas extinguishes burning splint with a pop sound

Question 31

reaction with bases process is called ___ and equation is

Answer 31

neutralisation acid + base = salt + water

Question 32

naming salts

Answer 32

first part comes from metal, metal hydroxide/oxide or metal carbonate second part: acid nitrate (nitric) chloride (hydrochloric) sulfate (sulfur) _ending of salt name_ (acid that produces salt)

Question 33

reactants are

Answer 33

substances that are present at the start of the of the reaction which interact with one another

Question 34

products definition

Answer 34

substances produced by the chemical reaction

Question 35

Why are the mass of reactants and products the same?

Answer 35

No new atoms are created and no atoms are destroyed

Question 36

a chemical equation helps to ____

Answer 36

summarise what had happened in a chemical reaction

Question 37

reaction of DILUTE acids with carbonate equation (all reactions with acids contain dilute acids)

Answer 37

acid + carbonate= salt + water + carbon dioxide gas

Question 38

aqueous definition

Answer 38

already dissolved in water

Question 39

test for carbon dioxide gas

Answer 39

passing gas through limewater

Question 40

2 main reactions involving bases

Answer 40

base and acid reaction base and ammonium salt

Question 41

bases and acid reaction is called

Answer 41

neutralisation

Question 42

base and ammonium salt reaction equation

Answer 42

base + ammonium salt== salt + water + ammonia gas

Question 43

definition of ammonium salts

Answer 43

compounds which contain ammonium polyatomic ion combined with another species, such as a chloride ion, nitrate ion or sulfate ion

Question 44

chemical change is a result of

Answer 44

chemical reaction

Question 45

alkalis produce what ions in water

Answer 45

OH- (hydroxide) OH-(aq)

Question 46

unreactive metals are

Answer 46

sliver, copper and gold

Question 47

universal indicator definition

Answer 47

a substance which will change colour due to changes in Ph like litmus paper

Question 48

alkali turns litmus paper

Answer 48

blue, like the colour of the seaa

Question 49

acids turn litmus paper

Answer 49

red, like the colour of the fiery flames

Question 50

pH scale is to

Answer 50

measure how alkaline or acidic a solution is

Question 51

range of pH scale

Answer 51

0-14

Question 52

pH levels of alkaline

Answer 52

8-14, greater than 7

Question 53

pH levels of acids

Answer 53

less than 7

Question 54

pH level of 7 means that the solution is

Answer 54

neutral

Question 55

very alkaline or very acidic solutions are usually

Answer 55

very corrosive and can burn our skin

Question 56

lower pH levels mean

Answer 56

that the solution is more acidic

Question 57

why must acids or alkalis be in a solution?

Answer 57

to activate and produce either H+ ions (for acids) or hydroxide ions (for alkalis) to activate their chemical properties

Question 58

all acids turn red with the universal indicator. True or false, and why

Answer 58

false. Weaker acids turn yellow or orange.

Question 59

pH 3 and below, red pH 4, orange pH 5, orange yellow pH 6, yellow pH 7, green

Answer 59

pH 8, teal pH 9, blue pH 10 and above, purple

Question 59

universal indicator definition

Answer 59

is a special indicator which is made from micing different indicators. can turn into different colours of the rainbow at different pH values.