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Why do ionic compounds like NaCl conduct electricity when dissolved but not when they’re solid, whereas metals conduct electricity when they’re solid?

Firstly, it's important to recognise that ionic compounds and metals are two different structures. Ionic compounds consist of positively charged ions and negatively charged ions held together by strong elect...
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Answered by Hannah B. • Chemistry tutor
43067 Views

When using cm3 as the unit for volume to calculate the concentration why must you divide the cm3 by 1000?

As I’m sure you already know, the units of concentration are mol dm -3 . So before we calculate concentrations we must convert the volume with units cm 3 to dm 3 . 1 dm is the equivalent of 10 cm . So, by cu...
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Answered by Hannah B. • Chemistry tutor
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Factorise completely ( x − 4x^3)

(x-4x 3 ) = x(1-4x 2 ) Just taking a factor of x out of both terms Within the inner bracket we have a difference of two squares. 1 2 =1 and (2x) 2 =4x 2 therefore we can write x(1-4x 2 ) = x(1-2x)(1+2x)
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Answered by Edward C. • Maths tutor
22883 Views

solve the differential equation dy/dx = 6xy^2 given that y = 1 when x = 2

First step is to seperate the variables (EQ1) : (1/y^2) dy = 6x Then we integrate each side seperately giving us (EQ2) : -1/y = 3x^2 + C (remembering to add 1 to the power and divide by the new power) subbin...
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Answered by Dylan M. • Maths tutor
10199 Views

How would you determine what sort of stationary point this curve has? x^3 - 6x^2 + 9x - 4

I would differentiate it and then turn it into an equation to find the points where the gradient equals zero. With these points at hand, I would take a second derivative, this tells me how the gradient chang...
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Answered by William M. • Maths tutor
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