Unit 4: Maths in Chemistry Flashcards
What is the moles equation?
Moles = mass / Mr
What does Mr stand for?
Relative molecular mass
What does Ar stand for?
Relative atomic mass
What is an isotope?
The same element with different neutrons
What is the conservation of mass law?
The mass of reactants = the mass of the products
How do you find the Ar for the element
It is it’s mass number (large number)
How do you find the Mr of a compound
Add up the masses of all the elements in that compound
State the relative charges of the subatomic particles
Protons: +1, neutrons: 0, electrons: -1
State the three subatomic particles
Protons, neutrons, electrons
Define element
A substance made of only one type of atom
Define compound
A substance made of two or more different atoms chemically bonded together
What is the atomic number of an atom?
The number of protons in an atom
What is the mass number of an atom?
The number of protons + the number of neutrons in an atom
How do you calculate the number of neutrons in an atom?
Mass number - atomic number
What is the concentration equation?
Concentration = mass/volume
How do you convert cm3 to dm3
Divide by 1000
What does (s) stand for?
solid
What does (l) stand for
liquid
What does (aq) stand for
aqueous (dissolved in water)
What does (g) stand for
gas
How do you measure the volume of a gas?
Using a gas syringe
Why does the mass of Mg go up when it is oxidised?
Because you are adding oxygen atoms to it
What are the steps for reacting masses?
1) convert known mass to moles
2) use the molar ratio to find the moles of the product
3) calculate the mass of the unknown substance
What are the steps for calculating concentration?
1) convert cm3 into dm3
3) Concentration =mass/volume
How do you measure the volume of a solution?
Using a measuring cylinder
How do you calculate the % mass of an element?
(mass of element/mass of compound) x 100
