# Calculate q when 286 g of water is heated from 220c

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Exam 2 1307 s18.pdf

Calculate q when 286 g of water is heated from 220C to 783C A674 kJ B161 10 3 from CHEM 1307 at Texas Tech University

20 )   Cold packs , whose temperatures are lowered when ammonium nitrate dissolves in water , are carried by athletic trainers when transporting ice is not possible . Which of the following is true of this reaction ?
A ) Δ H = 0 , since cold packs are sealed
B ) Δ H < 0 , process is endothermic
C ) Δ H > 0 , process is endothermic
D ) Δ H > 0 , process is exothermic
E ) Δ H < 0 , process is exothermic
21 )   Calculate q when 28.6 g of water is heated from 22.0 ° C to 78.3 ° C.
22 )   The combustion of glucose ( C 6 H 12 O 6 ) with oxygen gas produces carbon dioxide and water . This process releases 2803 kJ per mole of glucose . When 3.00 mol of oxygen react in this way with glucose , what is the energy release in kcal ? ( Hint : Write a balanced equation for the combustion process . )
23 )   Calcium hydroxide , which reacts with carbon dioxide to form calcium carbonate , was used by the ancient Romans as mortar in stone structures . The reaction for this process is 23 ) Ca ( OH ) 2 ( s ) + CO 2 ( g ) → CaCO 3 ( s ) + H 2 O ( g ) Δ H = – 69.1 kJ What is the enthalpy change if 3.8 mol of calcium carbonate is formed ?
24 )   Use Hess 's Law to calculate the enthalpy change for the reaction WO 3 ( s ) + 3H 2 ( g ) → W( s ) + 3H 2 O ( g ) from the following data : 2 W ( s ) + 3O 2 ( g ) → 2 WO 3 ( s ) Δ H = – 1685.4 kJ 24 ) 2H 2 ( g ) + O 2 ( g ) → 2H 2 O ( g ) Δ H = – 477.84 kJ
A ) 364.9 kJ
B ) 1207.6 k J
C ) 252.9 kJ
D ) 125.9 kJ
E ) None of these choices are correct .
25 )   Select the arrangement of electromagnetic radiation which starts with the lowest energy and increases to greatest energy .
26 )   The AM station KBOR plays your favorite music from the 20s and 30s at 1290 k Hz . Find the wavelength of these waves .