Amount Of Substance Flashcards

Question

1 kg in g ?

Answer 1

1. Calculate moles of CO2 using mass/mr 2. Multiply moles by the number of atoms of oxygen in the molecule (2)

Answer 2

Number of particles in a mole (6.02x10^23)

Answer 3

The amount of substance that has the same number of particles as there are atoms in 12g of C12 (avogadro’s constant) Can be applied to electrons, atoms, molecules, ions, formulas etc.

Answer 4

Mean mass of an atom of an element compared to 1/12 the mass of a C12 atom

Answer 5

Mean mass of a molecule/formula unit of a substance compared to 1/12 the mass of a C12 atom -formula refers to ions in an ionic compound -molecular refers to atoms in a covalent compound

Answer 6

It is the ratio of the actual mass obtained during an experiment compared to the highest theoretical yield. (based on the amount of substance that you have)

Answer 7

The conditions of the reaction, meaning that if we change the conditions to favour the reaction, we can maximise the yield.

Answer 8

1. An alternative reaction occurs, forming another product and less of our theoretical product 2. The reaction is reversible, so reaction does not reach completion 3. Product is lost during separation from the reaction mixture

Answer 9

A measure of how many of the reactant atoms from the reagent form the useful product(s), taking into account any byproducts

Answer 10

total Mr of useful product(s) / total Mr of reactants (total Mr in this scenario is calculated through the Mr of the formula x any balancing numbers)

Answer 11

It can only become higher in a certain reaction if we can find profitable uses for the "waste" products

Answer 12

Found from practical data, it is the simplest ratio of atoms in a compound

Answer 13

1. Separate all of the elements in the formula unit into their elements 2. Write out the %mass/mass of each element 3. Divide each of the masses by the Mr of the element 4. Divide all of the moles by the smallest mole 5. Find out the smallest whole integer ratio of all of the elements 6. Write out the formula with the number of each element

Answer 14

The actual number of atoms in each element in a compound (more useful for us to use during calculations)

Answer 15

Given Mr of the molecular formula / Mr of the empirical formula. We then multiply all of the numbers in front of each element by the number from the above calculation

Answer 16

Concentration (g/dm3) = mass (g) / volume (dm3) Concentration (mol/dm3) = moles (mol) / volume (dm3)

Answer 17

m3 -> dm3 (x1000) dm3 -> cm3 (x1000)

Answer 18

Temperature (directly proportional) Pressure (inversely proportional) Number of moles (directly proportional)

Answer 19

Temperature (directly proportional) Number of moles (directly proportional)

Answer 20

pV = nRT where : p = pressure (pascals) V = volume (m3) n = number of moles (mol) R = gas constant T = temperature (Kelvin)

Answer 21

8.314 KJ-1mol-1

Answer 22

As an substance may be a gas at a negative temperature. This would give us negative solutions, which are incorrect so Kelvin is used as it is absolute.

Answer 23

degrees Celsius + 273 (273 is absolute zero, so the Kelvin scale starts from this value)