What can you conclude about these two reactions based on the chemical equations? reaction a: 6co2(g) + 6h2o(l) + sunlight → c6h12o6(aq) + 6o2(g) reaction b: 2h2(g) + o2(g) → 2h2o(g) + energy a. reactions a and b are both exothermic. b. reaction a is endothermic, and reaction b is exothermic. c. reactions a and b are both endothermic. d. reaction a is exothermic, and reaction b is endothermic.

The correct answer is B: reaction A is endothermic and reaction B is exothermic.

Explanation:

A: 6CO2(g) + 6H2O(l) + sunlight → C6H12O6(aq) + 6O2(g): is the photosynthesis reaction. Photosynthesis is an endothermic reaction, therefore it needs energy (sunlight) to take place.

B: 2H2(g) + O2(g) → 2H2O(g) + energy: is the formation of water. It is an exothermic reaction which releases energy as a result of the reaction.

So, the answer is option (B): Reaction A is Endothermic and Reaction B is Exothermic.

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

i just learnt this recently but i need to look through my notes again