# Molar change in solution - Problem, tried solving dont understand

• Gold
In summary, the question asks how many degrees Celsius the temperature would rise if 4.0g of NaOH was dissolved in 50mL of water. The solution involves calculating the molar enthalpy change based on the information given, which results in a value of 36,575 kJ/mol. However, the attempted solution is incorrect and does not provide the correct answer of 37.0 Celsius.
Gold

## Homework Statement

How many degrees(Celsius) would the temperature rise if 4,0g of NaOH was initially dissolved in 50mL of water.

## Homework Equations

Calculate the molar enthalpy change of solution based on this information:

- 4g NaOH(s) gets dissolved in 250mL of water, and the temperature rose from 19,5 to 23.0 Celsius.
- 4.18 J to raise temperature in 1 gram of water 1 Celsius.
- Water density: 1,0g/mL.
- No energy was exchanged with the surroundings before the temperature change was measured.

I solved this and ended up with 36,575 kJ/mol

## The Attempt at a Solution

Here is what I`ve tried:

50ml of water = 50 grams
Molar mass of water: 18,016 g/mol

50/18,016= 2,7753 mol

2,7753 mol * 36,575 kJ/mol= 101kJ

101kJ * 1000= 101000 J

101000/4,18 J/g * Celsius=24162

24162/1000=24,16 Celsius ?

19,5+24,16= 43 Celsius??

I don't understand?
The correct answer is from 19,5 to 37.0 Celsius.

Last edited:
Gold said:
I solved this and ended up with 36,575 kJ/mol

Moles of what?

Do you mean 36.6 kJ or 36600 kJ?

## What is the concept of molar change in solution and why is it important?

Molar change in solution refers to the change in the concentration of a substance in a solution. It is important because it helps us understand the behavior of substances in a solution and how they interact with each other.

## What is the formula for calculating molar change in solution?

The formula for calculating molar change in solution is ΔC = (C₂ - C₁)/V, where ΔC is the molar change, C₂ is the final concentration, C₁ is the initial concentration, and V is the volume of the solution.

## How do you solve for molar change in solution?

To solve for molar change in solution, you need to know the initial and final concentrations of the substance in the solution. Then, plug these values into the formula ΔC = (C₂ - C₁)/V and solve for ΔC.

## What are the units for molar change in solution?

The units for molar change in solution are moles per liter (mol/L) or molarity. This unit represents the change in the number of moles of a substance in a liter of solution.

## What are some factors that can affect molar change in solution?

Some factors that can affect molar change in solution include temperature, pressure, and the presence of other substances in the solution. These factors can alter the behavior and interactions of the substances in the solution, resulting in a change in concentration.

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