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If an element has an atomic mass of 19 and a proton number of 9, how many neutrons does it have and how many electrons does it have?

The atomic mass is made up of all the protons and neutrons (which together form the nucleus) which each have a mass of approx. 1g. Therefore if the mass of the element is 19g and it has 9 protons (proton num...
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Answered by Jay T. • Chemistry tutor
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Calcium carbonate is burnt substance B is created. What is the formula for substance B and what is the equation when water is added?

Cao Cao + H20 --> Ca(OH)2
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Answered by Thomas N. • Chemistry tutor
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What is the difference between osmosis and diffusion.

Firstly, it is important to read the question, it says what is the difference so we need to look at the differences between the two processes. Diffussion is the movement of particles from an area of high con...
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Answered by Ashkun Z. • Biology tutor
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Solve the simultaneous equations: 6x +2y = 2 and 12x - 3y = 18

6x + 2y = 2 and 12x -3y =18 Start by multiplying the first equation by two in order to balance both equations to have equal numbers of x 12x + 4y = 4 and 12x - 3y = 18 Rearrange both equations so that the x ...
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Answered by Jack H. • Maths tutor
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Solve x2 +2x – 4 = 0, leaving your answer in simplest surd form (4 marks, non calculator question)

'Simplest surd form' is a clue that quadratic factorising will not work for this question, so we must instead use the quadratic formula. It is always a good idea to quote this as marks are often available fo...
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Answered by Fiona O. • Maths tutor
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