3.3 The mole and the Avogadro constant

Question 1

The formula of an ionic compound

Answer 1

To write the formula for an ionic compound, write the symbol of the positive ion and then the symbol of the negative ion. Add the subscripts that are needed to balance the charges. You need to show many electrons where taken(-) or given(+)

Question 2

Equations of chemical reactions

Answer 2

Word equation: Display of a chemical using the names of the (reactants–>products)
Symbol equation: Display of a chemical using symbols of the (reactants–>products)

Question 3

Molecular Formula

Answer 3

Is the number and type of different atoms in one molecule (NaCl)

Question 4

Balancing equations

Answer 4

A symbol that shows that for every element present there is an equal amount of atoms both sides of the equation

Question 5

Empirical formula

Answer 5

The simplest whole number ratio of atoms in a compound or molecules (H2O2–>OH)

Question 6

Relative molecular mass

Answer 6

The sum of the relative atomic masses of the element within a compound or molecule

Question 7

Calculating reacting masses

Answer 7

The total mass of reactants = The Total mass of products
Due to the conservation of mass

Question 8

Relative atomic mass

Answer 8

The average mass of an element on a scale in which the carbon 12 atom has a mass of exactly 12u

Question 9

Avogadro constant

Answer 9

the number of particles in one mole of a substance. 6.022x10*23

Question 10

How to calculate the amount of a substance

Answer 10

To calculate the amount of substance=Mass÷Molar mass

Question 11

Molar mass

Answer 11

The mass of one mole of a compound. Mr= mass dived by number of moles

Question 12

Molar gas volume

Answer 12

Gas volume= Number of moles÷24

Question 13

Molecular formula

Answer 13

A symbol that identifies the actual amount of each atom in a molecule or compound

Question 14

1 dm3 in ml, litre and cm3

Answer 14

1000ml
1L
1000cm*3

Question 15

How to calculate the amount of a substance

Answer 15

To calculate the amount of substance=Mass÷Molar mass

Question 16

how to calculate the purity of a substance

Answer 16

Purity%= mass of pure product ÷ mass of impure product obtanded(the sample) x 100

Question 17

same formula as density

Concentration

Answer 17

The amount of particles or moles in a given volume.
Concentration (g/dm3) = mass (g)÷volume (dm3)

Question 18

Molar concentration

Answer 18

The concentration expressed in moles of a solute per unit volume of solution.
Units mol/dm3.

Question 19

Tritration

Answer 19

Method used to determine the concentrations of two solutions that exactly react with one another.

Question 20

limiting reagent

Answer 20

The reactant in a chemical reaction that runs out first and therefore causes the reaction to start to slow down.

Question 21

percentage yield

Answer 21

actual yield÷theoretical yield×100