Only the second period class has homework tonight which is to complete the worksheet that deals with solving the concentration of a solution. I decided to assign this because we were unable to complete an exit slip due to the fire drill.
Here are some helpful notes about what we covered in class today.
We were reminded of two key words when it comes concentration. Those are dilute and concentrate. There is a more detailed description of these words in an earlier post but basically a dilute when the concentration of a solution is less than 50% and a concentrate is when a solution has more than 50% of a solute within it.
Here is the question that we spent a lot of time on today - How do I solve a concentration problem?
First a foremost, you all should remember the ratio that we set up in class today that will guide us through these problems. As we found out in class sometimes it is not necessary to use the percentage but rather the other side could be used to find out how much of a solute is needed in a larger amount of solution as well. The ratio is listed below...
Solute = % (concentrate) in solution
Solvent 100
There are a few things that must be remembered when using the above formula
- Solute is always the smaller of the two in the solution and usually going to be the smaller number, usually given in g, mL, or L
- Solvent refers to the total amount of the solution. Key words that will help you identify this number is ___ of solution or sample.
- When using a percentage of concentrate in a solution you always put the amount of concentrate over 100 because percentage is always measured on a scale up to 100. If not given concentrate percentage or asked for it, DO NOT USE THIS RATIO.
Here is a practice problem - What is the percentage of concentrate of a 450 mL solution that has a 35 g of salt dissolved within it.
First you decided what information you are given within the problem. Since the problem says 450 mL solution, I know that this is referring to the solvent. That would mean the smaller number 35 g would be the solute in the solution. Plug those figures in the ratio and you get...
35 g = %(concentrate) in solution
450 mL 100
Now you cross multiple to get the % of the solution by itself, which looks like this...
35 (100) = 450 (% [concentrate] in solution)
Now you divide each side by 450, which looks like...
3500 = % (concentrate) in solution
450
That gives you the answer...
7.78 % = concentrate in solution
Always remember that you must include the unit of measure so in this problem it is asking for the concentrate so the unit is percentage.
Here is the question that we spent a lot of time on today - How do I solve a concentration problem?
First a foremost, you all should remember the ratio that we set up in class today that will guide us through these problems. As we found out in class sometimes it is not necessary to use the percentage but rather the other side could be used to find out how much of a solute is needed in a larger amount of solution as well. The ratio is listed below...
Solute = % (concentrate) in solution
Solvent 100
There are a few things that must be remembered when using the above formula
- Solute is always the smaller of the two in the solution and usually going to be the smaller number, usually given in g, mL, or L
- Solvent refers to the total amount of the solution. Key words that will help you identify this number is ___ of solution or sample.
- When using a percentage of concentrate in a solution you always put the amount of concentrate over 100 because percentage is always measured on a scale up to 100. If not given concentrate percentage or asked for it, DO NOT USE THIS RATIO.
Here is a practice problem - What is the percentage of concentrate of a 450 mL solution that has a 35 g of salt dissolved within it.
First you decided what information you are given within the problem. Since the problem says 450 mL solution, I know that this is referring to the solvent. That would mean the smaller number 35 g would be the solute in the solution. Plug those figures in the ratio and you get...
35 g = %(concentrate) in solution
450 mL 100
Now you cross multiple to get the % of the solution by itself, which looks like this...
35 (100) = 450 (% [concentrate] in solution)
Now you divide each side by 450, which looks like...
3500 = % (concentrate) in solution
450
That gives you the answer...
7.78 % = concentrate in solution
Always remember that you must include the unit of measure so in this problem it is asking for the concentrate so the unit is percentage.
No comments:
Post a Comment