Mocks Flashcards

1
Q

Explain why ethanol isn’t a hydrocarbon (2)

A

hydrocarbons contain (only)
carbon and hydrogen
(however) ethanol contains
oxygen / O

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2
Q

Calculat ethe mass of 4 moles of neon atoms, Relative atomic mass of Ne=20 (2)

A

(mass =) 4 × 20
= 80 (g)

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3
Q

Which group of elements would form ions with a +1 charge

A

Alkali metals

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4
Q

Give one reason why solid sodium chloride doesn’t conduct electricity

A

Ions cannot move around

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5
Q

The structure of sodium chloride is a giant ionic lattice,describe the forces of attraction between the ions in solid sodium chloride (3)

A

(strong) electrostatic (forces of
attraction)
between oppositely charged
ions
(forces act) in all directions

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6
Q

Name the piece of equipment used to measure 10cm of dilute HCL

A

Measuring cylinder r

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7
Q

Explain why a white solid is produced when barium reacts with dilute sulfuric acid (2)

A

barium sulfate is produced
(which) is insoluble

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8
Q

Describe the relationship between the temperature of alkanes with he viscosity of alkanes

A

as the temperature increases
the viscosity decreases
change gets smaller as
temperature gets higher

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9
Q

A student investigated the viscosity of a hydrocarbon, the empirical formula was CH2, 0.31 moles had a mass of 43,4g. Determine the molecular formula for the hydrocarbon

A

mass of CH2 = 0.31 x 14 (1)
= 4.34 (1)
�43.4
4.34 =� 10 (1)
C10H20 (1)

=� 10
C10H20

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10
Q

What gas is produced when lithium reacts with water

A

Hydrogen

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11
Q

Metals react with group 7 elements and form a solid compound. Describe a chemical testt and the results to identify if the solid compound is iron(2) bromide or iron (3) bromide

A

Test- dissolve the solid in waterr and add sodium hydroxide, the iron 2 bromide willl show a green colored precipitate while the iron 3 bromide willl form a brown precipitate

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12
Q

Complete the half equation for the formation of hydrogen at the negative electrode __+_e- -> h2

A

2h+,2

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13
Q

Describe a method to find the mass of lead bromide precipitate (4)

A

Filter the mixture
wash the residue
dry the residue (and filter
paper)
weigh the (dry) lead bromid

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14
Q

Explain why calcium hydroxide solution is an effective chemical to remove lead ions (2)

A

calcium hydroxide solution has
a pH greater than 7
(and) a higher percentage of
lead ions are removed (above
pH 7)

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15
Q

Suggest what is meant by equilibrium (2)

A

When the rate f reaction is the same in each direction in a closed system

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16
Q

The contact process conditions are a vanadium oxide catalyst,450 degrees and atompsheric presssure. Explain why these conditions are used while referring too both yield and rate of reaction

A

rate
• higher temperature gives higher rate because of more
frequent collisions
• higher temperature gives higher rate because more
particles have the activation energy
• higher pressure gives higher rate because of more
frequent collisions
• use of catalyst gives higher rate because the activation
energy is lowered
equilibrium
• higher temperature decreases the yield because reaction
is exothermic
• higher pressure increases the yield because more
molecules on left-hand side
• use of catalyst has no effect on the yield
other factors
• higher temperature (than 450°C) uses more energy so
increases costs
• higher pressure uses more energy so increases costs
• higher pressure requires stronger reaction vessels so
increases costs
• use of a catalyst reduces energy costs
compromise
• the temperature chosen is a compromise between rate of
reaction and position of equilibrium
• the temperature chosen is a compromise between rate
and cost
• the pressure chosen is a compromise between yield / rate
and cost
• extra cost of higher pressure is not worth extra yield

17
Q

What environmental problem is caused by particulates

A

Global dimming

18
Q

Combustion of some fuels causes acid rain.explain why (3)

A

(there is) sulfur (in fuel)
(the sulfur) burns
to produce sulfur dioxide
OR
nitrogen combines with oxygen
(1)
at high temperature (1)
to produce oxides of nitrogen
(1)

19
Q

Evaluate the use of diesel fuel and hydrogen fuel to power cards (6)

A

Indicative content
• diesel comes from crude oil which is non-renewable
• diesel produces carbon dioxide that contributes to climate
change
• diesel produces particulates that contributes to global dimming
• hydrogen is produced from methane which is
non-renewable
• hydrogen only produces water so no pollutants are produced
• hydrogen is a gas so is more difficult to store
• hydrogen is a gas so takes up more space than diesel
• hydrogen gas is explosive
• hydrogen gas is not readily available
• more energy is produced per gram of fuel from hydrogen so a
smaller mass of fuel is used
• reasoned judgement

20
Q

Diesel contains decane (c10h22), 19500j of energy is released during the combustion of 0.426g of decane, calculate the energy change in kj from the combustion of 1 mole of decane

A

(Mr of decane =) 142
(mol of decane =
0.426
142 )
0.003 (mol)
(unit conversion =
19 500
1000 =)
19.5 (kJ)
(heat energy change
per mol =)
19.5
0.003
= (‒) 6 500 (kJ)

21
Q

Explain exothermic exactions in terms of bond breaking and making

A

energy must be supplied to
break bonds
(and) energy is released when
bonds are formed
(so) the energy needed to break
existing bonds is less than the
energy released to form bonds

22
Q

What’s meant by the word “element”

A

a substance made up of only
one sort / type of atom

23
Q

What property of transition metals makes them useful to increase the appearance of pottery

A

They’re colored

24
Q

Name the transition metal catalyst used in the haber process

A

Iron

25
Q

Explain how catalysts increase the rate of reaction (2)

A

(catalysts) provide a different
pathway for the reaction
(which has a) lower activation
energy

26
Q

Describe the bonding in transition metals

A

strong electrostatic forces of
attraction
(between) positive ions and
electrons
(outer) electrons are delocalised

27
Q

Write an ionic equation for the displacement of silver by copper

A

Cu + 2 Ag+ → Cu2+ + 2 Ag

28
Q

Explain why the displacement of silver from silver nitrate is described as reduction

A

(because) silver ions gain
electrons

29
Q

Ethanoic acid can be produced from ethanol by microbial action, what time of reaction is this

A

Oxidation

30
Q

Suggest why the boiling points of alcohols increase as the number of carbon atoms increase

A

intermolecular forces
(are) stronger (the higher the
number of carbon atoms)
(so) more energy is required to
overcome the forces

31
Q

Give 2 properties that make esters suitable for use in perfumes

A

distinctive / pleasant smell
volatile