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The enthalpy of combustion of ethanol is −1371 kJ mol−1 . The density of ethanol is 0.789 g cm−3 . Calculate the heat energy released in kJ when 1 dm3 of ethanol is burned.

1 dm3 of ethanol is equal to 1000 cm3, so the mass of ethanol used is =density x volume = 0.789 g cm-3 x 1000 cm3 = 789gMolar mass of ethanol = (2x12)+(6x1) +(1x16)= 46 g mol-1Moles of ethanol = mass/mola...

Answered by Sophie L. • Chemistry tutor

15758 Views

Company A has demand function q=2p+5, and supply function q=10p. What is equilibrium price and quantity

P=5/8Q=25/4

Answered by Tom E. • Economics tutor

1674 Views

A curve has equation 2(x^2)+3x+10. What is the gradient of the curve at x=3

Answered by Tom E. • Maths tutor

3626 Views

In an economy consumption=50, investment=60, government spending=160, imports=60 and exports=40. What is the aggregate demand of the economy

₂₅₀

Answered by Tom E. • Economics tutor

1741 Views

A curve has equations: x=2sin(t) and y=1-cos(2t). Find dy/dx at the point where t=pi/6

Since this question concerns parametric's, one may move to eliminate t from the equation to calculate dy/dx directly. However, in this case it is much easier to use the chain rule and realise that dy/dx=d...

Answered by Cameron H. • Maths tutor

5528 Views