quantitive chemistry- paper 1

Question 1

What happens with the Mass if it Seems to Change during conversation mass?

Answer 1

1)mass increases=one of the reactants is a gas that’s found in air
-Before the reaction, gas is floating around in the air. not contained in the reaction vessel, can’t account for its mass.
-gas reacts to form part of the product, contained inside the reaction vessel - so total mass of the stuff inside increases.
2)mass decreases=One products is a gas
-If the vessel isn’t enclosed, gas can escape from the reaction vessel as it’s formed.
-no longer contained in the reaction vessel - the total mass of the stuff inside the reaction vessel decreases.

Question 2

1)When Reactions Stop what does it mean?
2) what are reactants called that limit the reaction and what is this directly proportional?

Answer 2

1) reactants is used up. other reactants are in excess= added in excess to make sure other reactant is used up.
2) reactant that’s used up in a reaction=limiting reactant
-amount of product formed is directly proportional amount of limiting reactant.
=add more reactant there=more reactant particles to take part in the reaction= more product particles.

Question 3

1)whyHigh Atom Economy is Better for Profits and the Environment?
2)How can you use waste products?
3)What is a high atom economy?

Answer 3

1)Reactions with low atom economy=
-use up resources very quickly=
-waste materials= unsustainable
Low atom economy= aren’t profitable.
-Raw materials expensive to buy
-waste products, expensive to remove,

2)find a use for the waste products=gives useful “by-products” rather than useless ones.
3)highest atom economy are the ones that only have one product. atom economy of 100%.

Question 4

What other areas should you look at when considering which reaction to use? 3 (atom economy)

Answer 4

1.yield=rate of the reaction
2.position of equilibrium for reversible reactions
3.A reaction with a low atom economy, useful by-products

Question 5

What is a mole?

Answer 5

Avagrado constant= 6.02x10^23
1 mole= relative atomic mass or relative molecular mass=g

N= 14g
N2=28g

Question 6

Relative or molecular mass?

Answer 6

Add or multiply the number with their atomic mass to get the whole grams to get when 1 mole

Question 7

How to find a limiting reactant?

Answer 7

1) balance equations
2) reactants and products in grams (relative atomic masses)
3)ratio find multiplier

Question 8

Gradient

Answer 8

change in y/ change in x

Question 9

Uncertainty

Answer 9

range / 2
Mean of set+- Answer

Question 10

Percentage mass of an element in a compound?

Answer 10

Question 11

Relative atomic mass?

Answer 11

Question 12

Concentraion?

Answer 12

Question 13

Mean rate of a reaction?

Answer 13

Question 14

How many Moles of something?

Answer 14

Question 15

Number of particles in a substance?

Answer 15

Question 16

What is the percentage yield?

Answer 16

Question 17

Atom economy?

Answer 17

Question 18

Concentration?;TITRATION

Answer 18

Question 19

Volume of gas?

Answer 19

Question 20

Cm3 to dm3?

Answer 20

• do this before calculations

Question 21

Ratio figuring out grams?

Answer 21

Ratio check wether the ratio weight should be bigger or not

Question 22

Recurring decimals?

Answer 22

Don’t use them you must round

Question 23

mol/dm3-> g/dm3?

Answer 23

1. Find the relative atomic mass
2. Multiply that by the original value to make it g/dm3

Question 24

How to do a titration calculation?

Answer 24

1.write an equation
2.balance it
3. Write c, n ,v for each acid and alkali
4.convert vaules if needed before caulcating
5.moles of acid and alkali to figure out the mole ratio
6. Figure out missing vaules

Question 25

What is in a soultion?

Answer 25

Solute
Solvent= the one which is larger concentration

Question 26

How to simpfly equations?

Answer 26

-divide by amount of molecules on both reactant products