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A student carries out an experiment to determine the melting point of a waxy solid. She heats a sample until it melts, then measures and records its temperature as it cools down. Explain how the student could use her results to decide whether the waxy

...solid is a pure substance or a mixture. Firstly, she would need to plot a graph of temperature against time. Temperature remains constant at the melting point. The graph will show whether the solid is pur...
LE
8543 Views

Explain the lock and key model of enzyme action, including how they are denatured.

An enzyme is a protein that functions as a biological catalyst by speeding up chemical reactions and remaining unchanged by the reaction. The place on an enzyme where the molecule binds is called the active ...
LE
Answered by Lucy Erin S. • Biology tutor
12115 Views

Explain the role of the moderator in a fission reaction.

slows neutrons/reduces KE of neutrons so that neutrons can be absorbed by the U-235 nucleus to cause fission to release kinetic energy. (nuclear reactor and energy)
RJ
Answered by Rishi J. • Physics tutor
3189 Views

The straight line L1 passes through the points with coordinates (4, 6) and (12, 2) The straight line L2 passes through the origin and has gradient -3. The lines L1 and L2 intersect at point P. Find the coordinates of P.

Find equation of line 1 in terms of x. eg y=mx+c - Using gradient and points. Equation of line 2 is just y=-3xSo -3x=mx+c of line 1Find xSub into one equation to find the y point.Done
RJ
Answered by Rishi J. • Maths tutor
10909 Views

A ball, dropped vertically, falls d metres in t seconds. d is directly proportional to the square of t. The ball drops 45 metres in the first 3 seconds. How many metres does the ball drop in the next 7 seconds?

d = kt 2 . 45 = k x 3 2 . 45 = k x 9 (/9). 5 = k.3+7 = 10 seconds total as we are investigating the NEXT 7 seconds. d = kt 2 . d = 5 x 10 2 . d = 5 x 100d = 500m in 10 seconds. As the ball drops 45m in the f...
EN
Answered by Emily N. • Maths tutor
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