addition of 1.280g of zinc metal to 100mL of 0.3917 M HCl in a coffee-cup calorimeter causes the temperature to increase from 1 degrees celsius to 22.11 degrees celsius. What is the value of the change of Hrxn for the following equation:

Zn(s) + 2HCl(aq)-->ZnCl2(aq) +H2(g)
Assume the density and specific heat of the solution are 1g/mL and 4.18J/g

So far I know that you must multiply: (1.28g)(22.11-15)(4.18)=

I don't know what to do after this step

I am trying to find Kj/mol in reaction

Did you make a typo? From your work I assume Ti is 15 and not 1 as you posted.

Your q calculation is almost correct. It should be 100 mL x 4.18 x (21.11-Ti) = q in Joules.

Note it's the water you're heating and although the Zn absorbs a little heat you're ignoring that. 100 mL H2O with a density of 1.0 g/mL = 100 grams.
So you have q for the reaction. That's q for 1.28g Zn. Then delta H = q/1.28 x (atomic mass Zn/1 mol) = J/mol. Convert that to kJ/mol.

So I did: 100 x 4.18 x (21.11-15)=2553.98 then I divided it by 1.28=1995.29

and I multiply it by 65.28/1mol=12969. Divide it by 1000 to get 130kJ/mol but its still not the right answer =(

The problem says 22.11 and not 21.11 (and I made the same typo in my response) and atomic mass Zn is 65.38 and not 65.28.

Yes okay thank you! I figured it out.

To calculate the change in enthalpy (∆Hrxn) for the given reaction, you need to consider the heat transferred during the reaction and the moles of reactants involved.

First, let's calculate the moles of zinc (Zn) used. The molar mass of Zn is 65.38 g/mol.

moles of Zn = mass of Zn / molar mass of Zn
moles of Zn = 1.28 g / 65.38 g/mol

Next, calculate the heat transferred during the reaction.
q = mc∆T

The variables are:
- q: heat transferred
- m: mass of the solution
- c: specific heat of the solution
- ∆T: change in temperature

The mass of the solution can be calculated by multiplying the density of the solution (1 g/mL) by the volume (100 mL).

mass of the solution = density of the solution × volume
mass of the solution = 1 g/mL × 100 mL

Now, let's calculate ∆Hrxn using the balanced equation and the mole ratios.

From the balanced equation: Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
The stoichiometric coefficient of Zn in the balanced equation is 1.

Therefore, ∆Hrxn = q / moles of Zn

Substitute the values into the equation:
∆Hrxn = q / (1.28 g / 65.38 g/mol)

Now, let's calculate q first:
q = mc∆T
q = (mass of the solution) × (specific heat of the solution) × ∆T

Substitute the values into the equation:
q = (mass of the solution) × (4.18 J/g°C) × (22.11 - 1) °C

Calculate the mass of the solution using the previously calculated value:
mass of the solution = 1 g/mL × 100 mL

Now, substitute all calculated values into the equation:
∆Hrxn = [(mass of the solution) × (4.18 J/g°C) × (22.11 - 1) °C] / (1.28 g / 65.38 g/mol)

Simplify the equation and perform the calculation to find the value of ∆Hrxn.