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In fractional distillation the shorter hydrocarbons have lower boiling points and distil off first. Why?

Boiling points are determined by the interactions between the individual hydrocarbon molecules . The weaker the interactions, the less energy is required to boil the hydrocarbon and the lower the boiling poi...
HB
Answered by Hannah B. • Chemistry tutor
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Why do acids have low pHs and alkaline solutions have high pHs?

The pH scale is a measure of how many H + ions there are in a solution. The higher the concentration of H + , the lower the pH and the more acidic the solution is. For example, for HCl, dissociation can occu...
HB
Answered by Hannah B. • Chemistry tutor
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Solve the simultaneous equations, 3x + 2y = 4 (1) 4x + 5y = 17 (2)

Solving simultaneous equations by elimination; firstly you would multiply the first equation by 4 to get another equation which we will name (3), and multiply the second equation by 3 to get another equation...
AP
Answered by Akash P. • Maths tutor
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Trolley A carrying mass 10kg is moving at speed 5m/s, and collides with stationary Trolley B carrying a mass 5kg. Indicating which Law you would apply, what is the speed and direction of Trolley B if Trolley A's resulting movement is 2m/s to the left?

By the Law of Conservation of Momentum, I nitial Momentum=Final Momentum, in a closed system. Take movement to the right as + and to the left as - Therefore equate the two as such: Initial (A+B) = final (A+B...
PS
Answered by Parinita S. • Physics tutor
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Consider the Matrix M (below). Find the determiannt of the matrix M by using; (a) cofactor expansion along the first row, (b) cofactor expansion along the second column

Matrix M is -2 1 -4 1 -1 5 3 0 2 Let A be a square nxn matrix. Then, for each entry Aij (where 1 </= i < n, 1 </= j < n), the minor of Aij is A(^i;^j), the determinant of the (n - 1) (n - 1) matr...
ET
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