Quantitative Chemistry

Question 1

conservation of mass

Answer 1

the law of conservation of mass states that no atoms are lost or
made during a chemical reaction so the mass of the products
equals the mass of the reactants

Question 2

avogadro constant

Answer 2

The value of the Avogadro

constant is 6.02 x 10²³ per mole

Question 3

Ar stands for

Answer 3

relative atomic mass

Question 4

Mr stands for

Answer 4

relative molecular mass

Question 5

how to figure out atomic number of two isotopes

Answer 5

(75x35)+(25x37) / 100

Question 6

% mass of an element in a compound

Answer 6

% mass of an element in a compound = Ar x number of atoms of that element / Mr of whole compound x 100

Question 7

moles

Answer 7

mass / mr

Question 8

uncertainty

Answer 8

mean ± half the range

Question 9

percentage uncertainty

Answer 9

range of measurements/mean x 100

Question 10

1 decimetre is ….

Answer 10

1 dm³ = 1 litre = 1000 cm³

Question 11

concentration

Answer 11

concentration = mass of solute/ volume of solvent

Question 12

percentage yield

Answer 12

% yield = mass of product actually made/ mass of maximum theoretical mass x 100

Question 13

atom economy

Answer 13

% atom economy = relative formula mass of desired products/ relative formula mass of all reactants x 100

Question 14

concentration in moles

Answer 14

amount of solute (mol)/ volume of solution (dm ³)

Question 15

concentration when given the concentration

Answer 15

concentration(g/dm ³) / Mr

Question 16

room temperature

Answer 16

20°C

Question 17

pressure

Answer 17

1 atm