# enthalpy change

1. ### Need help with calculating change in enthalpy

I’ve got an assignment to solve this problem: Calculate the change in Enthalpy when 50cm3 if 0.2moldm-3 NaOH is added to 250cm3 of HCl. The initial temperature is 21.6C and it rose to 32.8C. I tried solving it by doing: Change in Enthalpy = ((250*4.18*11.2)/1000)/0.01 (0.01 from doing 0.05*0.2...
2. ### heat distribution

A colleague and I are lab partners and we have been working on this problem with no avail. The problem goes as follows: "While receiving a hot stone massage, an 82.93 g granite stone at a temperature of 84.5 degrees Celsius is placed in you hand, after 20 minutes the stone has cooled to your...
3. ### Could someone help me with these exercises please?

I'm having difficulty with these chemistry questions
4. ### Calculating PV work done at atmospheric pressure?

I need some help figuring out this problem. This is the original problem: How much PV work is done in kilojoules for the reaction of 3.74 mol of H2 with 1.87 mol of O2 at atmospheric pressure if the volume change is −23.9L? And we are given this reaction: The reaction between hydrogen and...
5. ### Determine ΔE reaction for each of the following reactions?

2NH3(g)+3O2(g)+2CH4(g)-->2HCN(g)+6H2O(g) 2Al(s)+3Cl2(g)-->2AlCl3(s) So i'm totally lost on how to go about this question. Help getting started would be greatly appreciated.
6. ### Exothermic and Endothermic help?

I need some help with a question for chemistry. I'm not quite sure how to figure this out. Help is appreciated! :) Identify each enthalpy change by name and classify each change as exothermic or endothermic. 1.1 mol NaCl (s) à 1 mol NaCl(l) 2.C4H10 O(l) à C4H10O (g) 3.H2O(g) à H2O (l)...
7. ### Enthalpy Pre-lab

I completed all of the other questions but there are 2 I wasn't sure how to do... Problem: A student conducts an experiment to determine the enthalpy of neutralization for phosphoric acid reacting with sodium hydroxide. The student combines 25.0mL of equimolar solutions of acid and base, both...
8. ### Determination of Enthalpy Change Lab

I already completed a lab using H3PO4 and NaOH to find the enthalpy change. I am now trying to do the post lab questions and do not understand some of them.... 1. Calculate the amount of heat energy. Use 1.11 g/mL for the density. Use 4.18 J/(g degrees celcius) as the specific heat. I got an...