Finding the concentration of X

In summary, to find the density of X in Part A, you divide the mass of X (10g) by the volume of X (4mL) to get a density of 2.5g/mL. In Part B, you use the given mass of X (7g) and the volume of the solution (100mL or 0.100L) to calculate the concentration of X, which is 70g/L or 7%. The density of X does not affect the concentration calculation.
  • #1
MagicMarker
1
0

Homework Statement


How do I find the Density of X (Part A) and how do I find the Concentration of X in a solution (Part B)?

Part A:
I have 4mL of X. The mass of 4mL of X is 10g. Calculate the density of X.

Part B:
I have 7g of X in 100mL of Water. Calculate the concentration of X.

The FINAL ANSWER must be written in BOTH "g/L" and as a percent (%).

Homework Equations


Density of X = Mass/Volume
Concentration of X = grams of solute/Litre of solution

The Attempt at a Solution


What did I do:
------------------
Part A:
I have 4mL of X. The mass of 4mL of X is 10g. Calculate the density.

Finding Density of X:
I have 10g of X. (10g is the mass)
I have 4mL of X. (I'm thinking that 4mL is the volume)

Density of X = Mass/Volume
Density of X = 10/4
Density of X = 2.5g/mL

Therefore, the density of X is 2.5g/mL.
------------------
Part B:
I have 7g of X in 100mL of Water. Calculate the concentration of X.

Finding Concentration of X:
I have 7g. (grams of solute)
I have 100mL of Water, which is 0.100L. (Solution in L)

Concentration of X = grams of solute/Litre of solution
[X] = 7/0.100
[X] = 70g/L

As a percentage:
70g/L = 70/1000 = 0.07 = 7%

Therefore, the concentration of 7g of X in 100mL of Water is 70g/L (7%).

-------------------------------------------

Thoughts:
You know how I calculated the density of X in Part A (2.5g/mL), don't I use that information to calculate the concentration of X in Part B?

Does the density of the solute matter when calculating the concentration of X? If so, how do I use 2.5g/mL (density of X) in order to calculate the concentration of X in 100mL of Water?

I hope you are able to help me.

Thank you!
 
Physics news on Phys.org
  • #2
MagicMarker said:
Thoughts:
You know how I calculated the density of X in Part A (2.5g/mL), don't I use that information to calculate the concentration of X in Part B?

Does the density of the solute matter when calculating the concentration of X? If so, how do I use 2.5g/mL (density of X) in order to calculate the concentration of X in 100mL of Water?

I hope you are able to help me.

Thank you!

No, the density of the solute does not influence its concentration if its mass is known. Think, before adding x to the solvent, it can be solid, and in the solution the molecules are dispersed. No sense to speak of the density of x.

You would need the density of x if its volume were given, to calculate the mass.

ehild
 

FAQ: Finding the concentration of X

What is the formula for finding the concentration of X?

The formula for finding the concentration of X is C = n/V, where C represents concentration, n represents the number of moles of X, and V represents the volume of the solution.

How do I determine the units for concentration of X?

The units for concentration of X depend on the units used for n and V in the formula. If n is in moles and V is in liters, then the units for concentration will be moles per liter (mol/L).

Can I use any volume of solution to find the concentration of X?

No, in order to accurately find the concentration of X, you must use the volume of solution that contains the known amount of X. This is usually measured in a lab using a pipette or burette.

What is the difference between molarity and molality when finding the concentration of X?

Molarity (M) is a measure of concentration based on volume of solution, while molality (m) is a measure of concentration based on mass of solvent. Molarity is more commonly used in chemistry, but molality may be preferred in certain situations.

How does temperature affect the concentration of X?

Temperature can affect the concentration of X in a solution, as it can cause the volume or mass of the solution to change. It is important to note the temperature at which the solution was measured and to use the appropriate formula for concentration at that temperature.

Back
Top