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In one experiment, the temperature of 50 g of water increased from 22.0 °C to 38.4 °C. The mass of alcohol burned was 0.8 g. Calculate the heat energy (Q) in joules, released by burning 0.8 g of the alcohol.

Key Equation: Q = mc ΔT Where: Q = heat transferred (J), m = mass of substance which is heated (g), c = heat capacity of water (J g -1 °C -1 ) and ΔT = temperature change for heated substance (°C) . c = 4.2 ...
DB
Answered by David B. • Chemistry tutor
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f(x) = 2x + c, g(x) = cx + 5, fg(x) = 6x + d. c and d are constants. Work out the value of d. 3 marks.

fg(x) = 2(cx+5) + c = 2cx+10+c [1 mark] fg(x) = 6x+d. fg(x) = 2cx+10+c 6x = 2cx and d = 10+c [2 marks] 3 = c and therefore d = 13 [3 marks]
HK
Answered by Heba K. • Maths tutor
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Consider the Supermarket Industry. Tesco dominates the market with a 43% market share. Its closest rival is Sainsbury's with 19% of the market. Outline the potential costs and benefits of a merger between the two supermarkets.

Benefits: Economics of scale- shown on graph (movement to lower part of LRAC curve) can potentially pass on cost savings Profitability shared resources High tax revenue for the government Costs: Monopoly pow...
HV
Answered by Himesh V. • Economics tutor
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balance equation : PCl5 + 4H2O → H3PO4 + HCl

fist look at the first molecule on the left of the equation, the first atom is P there's 1 mole and looking at the right there is also only one. the look at the next atom Cl which has five mole, on the right...
CM
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Calculating the charge of a molecule e.g In NH4 what is the charge of the nitrogen atom?

For the atom which you want to calculate the charge determine the number of valence electrons a free atom usually has. this is the number of atom on the outer shell so for nitrogen, it has 5 valence atoms . ...
CM
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