When 2.5000g of NaOH were dissolved in 49.0g water in a calorimeter at 24.0C, th

Question

When 2.5000g of NaOH were dissolved in 49.0g water in a calorimeter at 24.0C, the temperature of the solution went up to 37.1C.

a) is this dissolving process exothermic? yes or no?...... I said yes

b)Calculate qH2O using   q= (sp x m x deltaT) ..........I got 2685.7096 J (2.68x10^3)

c) Calculate the mass of the solution (NaOH + H2O)...........I got 51.5g

d) find qrxn for the entire reaction (water and NaOH) as it occured in the calorimeter. use q rxn = q soultion = delta H reaction........I got -2822.73 J or -2.82x10^3

e) find qrxn (using part d) for the dissolving of 1.00g NaOH in water.

f) find delta H rxn (using part e) for the dissolving of 1.00 mole of NaOH in water.

thank you so much for your help! please show steps!!

Explanation / Answer

a) Yes it is exothermic since heat is released

b) qH2O = 49 x 4.18 x (37.1 - 24) = 2683.142 J

c) Mass = 49 + 2.5 = 51.5 g

d) q = 51.5 x 4.18 x (37.1 - 24) = 2820.037 J

e) For 1 g of NaOH q = 2820.037 / 2.5 = 1128.015 J

f) For 1 mole NaOH q = 1128.015 x 40 = 45120.592 J

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