28g of NH3 is dissolved in 500mL of water. What is the concentration of the resulting solution?
(I do not understand how to solve this. If you can explain, that'd be great!)
First you didn't say what units you want for the concentration. That can be g/L, g/mL, kg/L, mols/L, equivalents/L, etc. .
MOST posts here want mols/L = M so that is what I will do.
Molarity of a solution is the number of moles/liter of solution or M = mols/L.
You are not given mols in the problem. You are given grams so you much convert that to mols.
You do that this way. mols = grams/molar mass
grams in the problem is 28. Molar mass NH3 is 14+3 = 17 so
mols = 28/17 = 1.647. To two places that rounds off to 1.6 mols.
Then you plug into M = mols/L of solution.
mols from above is 1.6.
L of solution is 500 mL or 0.500 L so
M = 1.6/0.500 = ? M
This is picky but let me point out something in the problem. The problem says the NH3 is dissolved in 500 mL of water. BUT, and this is a big but, the definition of M is mols/L OF SOLUTION and that is NOT the same as dissolving in 500 mL of water. That 500 mL of water will expand and will NOT be 500 mL OF SOLUTION. So the problem should have said "assume the addition of NH3 does not change the volume" (or something like that) OR it should have given you some way to calculate the new volume. It's just a poorly worded question. But with the understanding that we assume no volume change then my solution above is correct. Another possibility is that you want the concentration is molality (not molarity) in which case the problem is worked another way.
Also, dissolving NH3 into water creates NH4OH. So, technically the answer will be wrong. However, conceptually and mathematically the answer is correct.
Oh, concentration! That's a serious topic, but don't worry, I'll clown around with it to make it more fun! To find the concentration of the solution, we need to use the formula:
Concentration = Amount of solute / Volume of solution
In this case, you have 28 grams (g) of NH3 as the solute and 500 milliliters (mL) of water as the solution. All we need to do now is plug these values into the formula:
Concentration = 28g / 500mL
Now, to make things easier, let's convert milliliters to liters because liters are cooler. There are 1000 milliliters in a liter, so:
Concentration = 28g / 0.5L
Now, let's do a little math magic:
Concentration = 56g/L
And voila! The concentration of the resulting solution is 56 grams per liter, or 56g/L. Ta-da!
To find the concentration of a solution, we can use the formula:
Concentration (C) = amount of solute (in grams) / volume of solution (in liters)
Given:
Amount of solute (NH3) = 28g
Volume of solution = 500mL
Step 1: Convert the volume of solution to liters.
Since 1 liter = 1000 mL, we can convert 500 mL to liters as follows:
500 mL ÷ 1000 mL/L = 0.5 L
Step 2: Plug the values into the formula to calculate the concentration.
C = 28g / 0.5 L
Step 3: Calculate the concentration.
C = 56 g/L
Therefore, the concentration of the resulting solution is 56 g/L.
To find the concentration of a solution, we need to know the amount of solute (in this case, NH3) dissolved in a given volume of solvent (in this case, water). The concentration is typically expressed in terms of moles of solute per liter of solution.
In order to solve this problem, we need to follow a few steps:
Step 1: Convert the given mass of NH3 to moles.
To do this, we need to know the molar mass of NH3, which consists of one nitrogen atom (N) and three hydrogen atoms (H). The molar mass of nitrogen is approximately 14.01 g/mol, and the molar mass of hydrogen is approximately 1.01 g/mol.
Molar mass of NH3 = (1 mol N × 14.01 g/mol) + (3 mol H × 1.01 g/mol) = 17.03 g/mol
Next, we can calculate the number of moles of NH3 by dividing the given mass by the molar mass:
moles of NH3 = 28 g / 17.03 g/mol ≈ 1.64 mol
Step 2: Convert the volume of the solution from mL to L.
Since concentration is typically expressed in liters, we need to convert the given volume of 500 mL to liters by dividing by 1000:
volume of solution = 500 mL / 1000 mL/L = 0.5 L
Step 3: Calculate the concentration.
Finally, we can calculate the concentration by dividing the number of moles of NH3 by the volume of the solution:
concentration = moles of NH3 / volume of solution ≈ 1.64 mol / 0.5 L ≈ 3.28 mol/L
Therefore, the concentration of the resulting solution is approximately 3.28 mol/L.