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Define relative formula mass (Mr) and calculate the relative formula mass of CaCO3. (Ar: Calcium= 40; Oxygen= 16; Carbon= 12)

The relative formula mass (Mr) of a compound is the sum of the relative atomic masses of the atoms in the numbers shown in the formula. Relative formula mass (Mr) of CaCO3 = 40+12+(3x16)=100.
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How does the body regulate heat?

Body temperature is regulated by a thermoregulatory centre in the brain, the hypothalamus. The hypothalamus can sense the temperature of the blood via receptors. The skin also contains temperature receptors ...
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Answered by Natasha C. • Biology tutor
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Solve 4x^2 - 3x - 4 = 0

There are two different methods of solving this equation and it is important to find the method that you find easiest. The first method is to split up the numbers and the letters on both sides of the equatio...
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Answered by Oliver H. • Maths tutor
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The circle c has equation x^2+y^2 = 1 . The line l has gradient 3 and intercepts the y axis at the point (0, 1). c and l intersect at two points. Find the co-ordinates of these points.

When approaching intersection problems, it is important to have both equations and solve them by substituting one into the other or simultaneously. First we need to find the equation of the line l since we a...
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Answered by Ellen T. • Maths tutor
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How can I improve my understanding of spoken French?

If you're planning on spending some time in France - and with the French, understanding spoken French is essential. Thankfully, there are not nearly as many accents in France as there are in the English-Spea...
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Answered by Agathe D. • French tutor
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