4.The reaction of 0.25 g magnesium with 100.0 mL of 2 M hydrochloric acid (density d = 1.039 g/ml) raises the temperature of the solution from 20.0 °C to 35.0 °C. The specific heat for HCl is 3.98 J/(g. C). Mg(s) + 2HCl(aq) —> MgCl2(aq) + H2(g) Calculate the heat of the reaction. (Use the equation Q = s . m .ΔT where s is the specific heat, m is the mass of solution and ΔT is the change in temperature)

Explanation:

Hello,

In this case, for the given equation to compute the heat, we should compute the mass of the solution of hydrochloric acid, thus, the first step is to compute its reacting mass:

Then, we obtain the total mass of the formed solution:

In such a way, we can infer that the specific heat of the solution is mainly the specific heat of hydrochloric acid, therefore the heat turns out:

Regards.

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

thats a little if u want the answer just look it up on google thats what i do haha : )