# chem

The Mass number of an element is what?
The amount of protons and neutrons added together.
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The atomic number of an element is what?
The amount of protons.
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How do you work out the amount of neutrons?
The mass number-the atomic number.
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How do you work out the amount of electrons?
The amount of electrons is the same as the amount of protons,so whatever the atomic number is that is how many electrons there are.
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What is the mass and charge of a proton and where can a proton be found?
Mass:1 Charge:+ Found:Nucleus
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what is the mass and charge of a neutron and where can a neutron be found?
Mass:1 Charge:0 Found:Nucleus
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What is the mass and charge of a electron and where can a electron be found?
Mass:1/2000 Charge:- Found:outer shell
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What is the Relative Atomic Mass(Ar)?
'The atomic mass of 1 atom of an element'
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How do you work out the Relative Atomic mass(Ar)?
It is the atomic number of an element.(Mass of neutrons and protons)
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What is the Relative formula mass (Mr)?
The mass of a 1 molecule of a compound
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Work out the relative formula mass of H2O?
H=1(X2)2 O=16 H20=18
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Work out the relative atomic mass of Oxygen?
O=16
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What is a mole?
The relative formula mass in grams.
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How do you work out 10 moles of Hydrochloric acid (HCl)?
Work out one mole:HCl H=1 Cl=35.5 HCl=36.5g (one mole) X 10=365g
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What is the percentage yield?
The percentage of product you have compared to what was possible.
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How do you work out the percentage yield?
Amount of product produced /divided by/ Amount of product possible X100
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50kg of calcium carbonate(CaCO3) is expected to produce 28kg of calcium oxide(Cao)A company heats 50kg of calcium carbonate in a kiln and obtains 22kg of caclium oxide.Calculate the percentage yield.
22/divided by/28 x100= 78.6%
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Few chemical reactions have 100% yield,give two reasons why?
1) Sometimes the product may of been left behind in the apparatus. 2)The reactants may not be completely pure.
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What is the percentage mass of an element?
How much of a certain element is in a certain compound.
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How do you work out the percentage mass of an element?
Atomic mass of element /divided by/ Formula mass of compound x100
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How do you work out the relative formula mass(Mr)?
The relative atomic mass of each element within the compound added together.
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Work out the percentage mass of Carbon in a molecule of carbon dioxide(Co2)
C=12 O=16(x2)=32 C=12 /divided by/ Co2=44 x100=27%
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What is the empirical formula?
The simplest whole number ratio of the elements in a compound
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Work out the empirical Formula of an oxide of iron produced by reacting 1.12g or iron with 0.48 of oxygen(Ar Fe=56 O=16)
Fe203
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What is Gas chromotography?
The separating of a sample.
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What do three peaks of the computer suggest?
That there are 3 substances in the sample.
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Why is there an oven involved?
So that the sample can be turned to a gas so it can flow through the column.
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Why is the column narrow and coiled?
To allow minimum surface area to be used up.
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What are the benefits of this new technology?
1)Its quicker. 2)Only a small sample is needed. 3)It is more accurate.
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What is mass spectrometry?
Identifying the sample based on its relative formula mass.
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What is the last peak on the mass spectrometer?
The molecular ion peak,which gives the relative molecular mass/formula mass of the substance.
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What is the rate of reaction?
The time take for the reactants to become products.
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The rate of reaction can be measured by.....
1) the rate at which the reactants are used up. 2)the rate at which the produts are produced.
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The rate of reaction can be worked out two ways...What are they?
1)Measuring the amount of reactants used. 2) Measuring the amount of products formed.
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What 4 things can affect the rate of reaction?
-Temperature -Surface Area -Concentration&pressure -A catalyst
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Why does an increase in temperature increase the rate of reaction?
Because increase the temperature gives the atoms or molecules more energy which means they move faster which means collisions occur more often and are more likely to be successful.
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What must happen for substances to react?
The atoms or molecules must collide with sufficient energy.
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What type of energy is need for the collisions?
Activation energy.
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High concentration increase the rate of reaction because?
Because the particles are crowded and close together,meaning they collide more often,so more collisions are successful.
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Low concentration decreases the rate of reaction because?
Beacuse the particles are spread out and so collisons occur less frequently meaning collisions are less successfully.
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What 4 things does a catalyst do?
1)reduces the amount if energy needed for successful collisions. 2)makes a surface for the particles to attach to which increase the collisions. 3)makes collisions more succesful. 4)speeds up reaction.
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Why is a catalyst import for industry?
Because they increase the rate of reaction and reduce the costs.
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Different .................. require different ....................
-reactions -catalysts
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A catalyst doesn't get .............or ................
-used up -altered
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If a chemical reaction gives energy to the surroundings, then what type of reaction is it?
Exothermic.
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If a chemical reaction takes in energy from the surroundings,then what type of reaction is it?
Endothermic.
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Exothermic reactions release.......energy than what is supplied.
-More
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Endothermic reactions release ........energy than what is supplied.
-Less
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In an .......... reaction products have more energy than reactants.
Endothermic.
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In an ...............reaction products have less energy than reactants.
Exothermic.
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In a reversible reaction,if the reaction is endothermic,then what is it the other way?
Exothermic.
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## Other cards in this set

### Card 2

#### Front

The atomic number of an element is what?

#### Back

The amount of protons.

### Card 3

#### Front

How do you work out the amount of neutrons?

### Card 4

#### Front

How do you work out the amount of electrons?

### Card 5

#### Front

What is the mass and charge of a proton and where can a proton be found?