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Home: Substituting in Formulae

CCE 19

CCE 19: Substituting in Formulae

Multiple Choice Example

Short Response Example

Item 6

A catering store sells espresso cups of various sizes. The interior of each cup is cylindrical in shape and each has an internal depth of 32mm, but their internal diameters differ.

If 30mL of espresso makes up a single shot, calculate the minimum internal diameter of a cup that would allow a double shot of espresso to fit within it.

Reminder: volume of a cylinder = Πr2h    1mL = 1cm3

Show all steps.

Give the diameter to the nearest mm.

(NB: three quarters of a page is given for your answer.)

Answers

Item 7:   A

Item 29: C

 

To achieve an A-grade, a response had to show that the capacity was determined by doubling the 30 mL single shot, then converting this to a volume of 60 cm3. To successfully solve for the radius, the volume and the internal depth of the cup had to use consistent units. For example if 60 cm3 was used as V then h would need to be 3.2 cm. The radius once found had to be doubled and rounded correctly to give the minimum diameter to the nearest millimetre.