Units and Measurements

Question 1

What are the different SI units for length, mass, atoms, time, electric current, temperature?

Answer 1

Length= Metre, M
Mass= kilogram, kg
Atoms= mole, mol
Time= second, s
Electric current= ampere, A 
Temperature= kelvin, K

Question 2

What are the SI units for area, volume, speed, acceleration and density?

Answer 2

Area= metres squared, m²
Volume= metres cubed, m³ or Litre (1dm^3)
Speed (velocity)= metre per second, m/s
Acceleration= metres per second squared, m/s^2
Density= kilogram per metres cubed, kg/mg^3

Question 3

What is an exponent?

Answer 3

Its the power…

Question 4

What are the rules for exponents?

Answer 4

Its on paper…

Question 5

1 = ? milli (m) = ? micro (μ) = ? nano (n)

Answer 5

1= 1,000milli

1= 1,000,000 micro

1= 1,000,000,000 nano

Question 6

What must you remember to do when you convert volume to the SI units?

Answer 6

It is to the power of

So for m³ = 100cm x 100 cm x 100cm = 10^6 cm^3
Therefore 1cm^3= 10^-6 m³

Question 7

What is the SI unit for molar mass?

Answer 7

It is grams per mol (g/mol)

Question 8

What is the formula for working out the amount of molecules? What is the definition of mole?

Answer 8

Molecules= moles x Avogadro’s constant (6.02 x10^23)

Having the same number of molecules as there are atoms in 12g of carbon-12

Question 9

What is the formula for concentration?

Answer 9

Concentration (molarity in mol L^-1 or M) = number of moles (mol) / Volume (L)

Molarity= Number of moles of a substance are contained in one litre of solution

Question 10

Which formula do you use for diluting solutions?

Answer 10

C1V1 = C2V2