Core Practical 2

Question 1

what is a standard solution?

Answer 1

one of known concentration

Question 2

how do you make a standard solution?

Answer 2

measure mass of acid solid required
transfer into volumetric flask (washings from beaker)
add 100cm3 of distilled water to dissolve solid
add more distilled water up to graduation line. invert.

Question 3

what is the weighing by difference technique?

Answer 3

mass of substance = mass weighing dish and substance - mass of dish after substance transferred.

Question 4

what are concordant results?

Answer 4

titres within 0.1cm3 of each other

Question 5

what are some common potential hazards and risks in a lab (generally) ?

Answer 5

Bunsen burner - burns - keep away from flammable chemicals and away from edge of desk
Chemicals- irritant, corrosive, toxic, flammable - handle with care, wear gloves, eye protection, away from open flame
Glassware- could break and cut you - handle with care keep away from edge of desk

Question 6

What piece of equipment do you take 2 readings from and therefore need to x2 when working out percentage uncertainty?

Answer 6

burette

Question 7

If you need to scale up to find the no. of moles in the full volume of solution in the volumetric flask use the equation…

Answer 7

moles in full volume =

full volume/ volume which you know no.of moles