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How to plan a A Level History source question?

Extract A Argument Claims: Judgement in response: Factual Information to the validity (or not) of claims: Summary of Paragraph: Extract B Argument Claims: Judgement in response: Factual Information to the va...
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Answered by Ines D. • History tutor
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For the equilibrium reaction PCl5(g) (equilibrium arrow)-> PCl3(g) + Cl2(g) explain the effect of increasing the concentration of Chlorine gas using the equilibrium constant.

Kc=[Cl2(g)][PCl3(g)]/[PCl5(g)] for this reaction. The rate constant is not affected by changes in concentration and hence an increase in the concentration of Chlorine causes an increase in the concentration ...
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Answered by James H. • Chemistry tutor
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A general function f(x) has the property f(-x)=-f(x). State a trigonometric function with this property and explain using the Maclaurin series expansion for this function why this property holds. Write down the integral in the limits -q to q of f(x) wrt x

Note that this property is the definition of an odd function, or draw a sketch of what this looks like in general about the horizontal axis. E.g. f(x)=sin(x) which has the expansion f(x)=x-((x^3)/3!)+((x^5)/...
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Answered by James H. • Maths tutor
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What happens to the pressure inside a gas-filled ball when the temperature is increased? Explain your answer, stating the assumption made.

From definition of pressure have P=F/A (in reality for a ball we are talking about infinitesimal areas, but the general definition is sufficient at this level). Assume that the area of the surface under cons...
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Answered by James H. • Physics tutor
2548 Views

How do I know if an enthalpy change should be positive or negative?

A negative enthalpy change represents an exothermic change where energy is released from the reaction, a positive enthalpy change represents an endothermic reaction where energy is taken in from the surround...
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Answered by Alex S. • Chemistry tutor
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