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How many Protons, Neutrons and Electrons are there in an atom of Silicon, Si?

Using a copy of the periodic table, look up the Mass and Atomic numbers of Silicon. Mass number = 28; Atomic number = 14. The Atomic number is equivalent to the number of Protons in an atom, so there are 14 ...
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Answered by Eloise S. • Chemistry tutor
176210 Views

Given a right-angled triangle with an angle of 35 degrees and an Opposite side of 12cm, calculate the length of the hypotenuse to 3 significant figures.

First, determine which of SOH-CAH-TOA you need to use. As this question involves the Hypotenuse and the Opposite side, use Sine. As such, write out the equation as: sin(35) = 12/x. (Let x represent the Hypot...
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Answered by Eloise S. • Maths tutor
9125 Views

Solve for x to 3dp: x^2 + 6x + 2 = 0

We cannot factorise this so we shall use the quadratic formula instead.We need to substitute in the values for a, b, and c.ax 2 + bx + c = 0x 2 + 6x + 2 = 0a = 1, b=6, c=2Once substituted in, we get 2 values...
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Answered by Rikesh S. • Maths tutor
3682 Views

Solve for x: x^2 + 6x + 8 = 0

First of all we must factorise this:x 2 + 6x + 8 = 0(x+4)(x+2) = 0Now we make each bracket = 0 and solve for x.x+4 = 0 x+2 = 0 x = -4 x = -2
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Answered by Rikesh S. • Maths tutor
4809 Views

A square, with sides of length x cm, is inside a circle. Each vertex of the square is on the circumference of the circle. The area of the circle is 49 cm^2. Work out the value of x. Give your answer correct to 3 significant figures.

The question tells us that the area of the circle is 49cm 2 , therefore we are able to form the equation πr 2 =49 (where r = radius of the circle). We can now work out the radius of the circle by rearranging...
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Answered by Sian J. • Maths tutor
23750 Views