Top answers

You have 3.51g of hydrated zinc sulphate. You heat up the zinc sulphate until all the water has evaporated from it. The weight after heating is 1.97g. Find how many H2O molecules per zinc sulphate molecule there are in the hydrated form of it.

Write down the equation: ZnSO4xH2O --> ZnSO4 + xH2O 2. Calculate the masses: 3.51g --> 1.97g + 1.54g 3. Calculate the number of moles, using the molar mass of water and zinc sulphate: 1.97g = 0.0122mol...
OS
Answered by Olivier S. • Chemistry tutor
22749 Views

Mandarin GCSE exam question, involving a reading and true/false answers

For this section of the GCSE mandarin exam, my strategy would be to first read through the question section, to make sure the student understands what it is that they are asking for. Due to time limit in the...
MG
Answered by Maddy G. • Mandarin tutor
1744 Views

In 5V circuit has two 2 Ohm resistors in parallel, what is the current passing through each resistor?

To solve this question we need to remember the equation "Voltage = Current x Resistance". The next step is to draw out the circuit. A 5V circuit means the battery is supplying 5V to the current. Tw...
MR
Answered by Mia R. • Physics tutor
11296 Views

What are elastic and inelastic collisions? After a head on elastic collision of two balls of mass m1 and m2, deduce an equation relating the final and initial velocities of both balls.

Elastic collisions conserve both linear momentum and kinetic energy, whereas inelastic collisions conserve only linear momentum. The derivation will be shown on the virtual black board.
JP
Answered by Jason P. • Physics tutor
3634 Views

Why do we have to use radians instead of degrees?

Radians are used a lot in A level maths because at higher levels, they allow for simplification of trigonometric functions. For example, when using radians, it can be said that: Sin(angle) ≈ angle Cos(angle)...
JS
Answered by Jamie S. • Maths tutor
8750 Views