Saturday, March 30, 2019
3/29 Chemistry Update and homework due 4/5
Hi folks,
This week we took a look at the concept of concentration. Basically, how many particles of something is in a solution. We worked a few molarity problems and some concentration problems. Then we did a fun lab where we used these concepts to discover what molarity of lemonade tastes the best.
For homework please do the enclosed worksheet. Several of these are two step problems so you need to convert to moles first. Answers are included so you can make sure you are on the right track.
Also, please answer the following questions regarding the lab. Answers below.
1. The lemonade container had a mass of 536g. How many moles of lemonade was in the container (just use the molar mass of sugar, C12H22O11, for the molar mass of lemonade)?
2. How many particles of "lemonade" is in the container (in other words, convert moles to particles)?
3. You've discovered that .25 M is the perfect molarity for a perfect tasting lemonade. You are having a party and want to impress all your friends, so you need to make 3 liters of lemonade. What mass of powder would you need? You need to convert moles to mass here. (See, and you thought chemistry wasn't useful.)
4. Whoops. .25M is way too sweet. Let's dilute that to .2M. How much water do you need to add. Use C1V1 = C2V2 here.
5. If you poured the entire jar, all 536g of lemonade, into a 2.2 liters (a gallon) jar, what would the molarity be?
Answers:
1. 1.57 Moles
2. 9.4 x 10^23
3. .25 = m/3 .75 moles so .75x 342 g/mol = 256.5g
4. C1V1 = C2V2
.25 x 3 = .2 x V2
3.75L = V2 So you need to add .75 L of water to dilute it.
5. 1.57/2.2 = .71M (That might be a bit sweet.)
This week we took a look at the concept of concentration. Basically, how many particles of something is in a solution. We worked a few molarity problems and some concentration problems. Then we did a fun lab where we used these concepts to discover what molarity of lemonade tastes the best.
For homework please do the enclosed worksheet. Several of these are two step problems so you need to convert to moles first. Answers are included so you can make sure you are on the right track.
Also, please answer the following questions regarding the lab. Answers below.
1. The lemonade container had a mass of 536g. How many moles of lemonade was in the container (just use the molar mass of sugar, C12H22O11, for the molar mass of lemonade)?
2. How many particles of "lemonade" is in the container (in other words, convert moles to particles)?
3. You've discovered that .25 M is the perfect molarity for a perfect tasting lemonade. You are having a party and want to impress all your friends, so you need to make 3 liters of lemonade. What mass of powder would you need? You need to convert moles to mass here. (See, and you thought chemistry wasn't useful.)
4. Whoops. .25M is way too sweet. Let's dilute that to .2M. How much water do you need to add. Use C1V1 = C2V2 here.
5. If you poured the entire jar, all 536g of lemonade, into a 2.2 liters (a gallon) jar, what would the molarity be?
Answers:
1. 1.57 Moles
2. 9.4 x 10^23
3. .25 = m/3 .75 moles so .75x 342 g/mol = 256.5g
4. C1V1 = C2V2
.25 x 3 = .2 x V2
3.75L = V2 So you need to add .75 L of water to dilute it.
5. 1.57/2.2 = .71M (That might be a bit sweet.)
Saturday, March 23, 2019
3/22 Chemistry Class update and homework due 3/29
Hi folks,
This week we took some time to see what is required to make reactions happen and what can be done to influence the rate of reactions.
We also took the time to do a fun brainteaser lab where the students were required to separate a mixture into its component parts using only one "tool" per separation. We then found the percentage composition of the materials in the mixture.
For homework this week:
Read pages 271 - 288 in the text.
Do Review Questions 1 - 28 on pages 301 and 302 (Many of these are review from earlier in the year)
This week we took some time to see what is required to make reactions happen and what can be done to influence the rate of reactions.
We also took the time to do a fun brainteaser lab where the students were required to separate a mixture into its component parts using only one "tool" per separation. We then found the percentage composition of the materials in the mixture.
For homework this week:
Read pages 271 - 288 in the text.
Do Review Questions 1 - 28 on pages 301 and 302 (Many of these are review from earlier in the year)
Saturday, March 16, 2019
3/15 Chemistry update and Homework due 3/22
Hi folks,
Today we took the time to take a look at the entire year. I find that students are so busy learning new thing, after new thing, after new thing that they don't really have the chance to put things in context or perspective, so I like to take some time every now and then to unpack what we've learned and take another look at it.
We also learned some vocabulary to classify different substances.
For homework this week:
Answer questions 1 - 22 on page 64 (No Math!!!!)
Friday, March 15, 2019
Extra Credit possiblility
Hi folks,
Here's an extra credit possibility. I'll give you one point of extra credit for every item in the shopping list you get right.
Also, don't forget the other extra credit possibilities. 10 points of extra credit if you recite the periodic table. 10 points if you can give me the name/symbol for every element on the periodic table. 10 points for reading the Disappearing Spoon and answering questions about it.
Good Luck!
Monday, March 4, 2019
3/1 Chemistry update and homework due 3/15
Hi folks,
Today we spent a small amount of time reviewing some of our recent problems and then introduced the concept of percentage yield.
For homework this week I'd like you to:
1. Do the .pdf called "Questions for Limiting Reagents Lab".
2. To practice more of these, I've included "Limiting Reagents and Percentage Yield Worksheet." I've included the answers in there for you as well.
Spring Break!
Hi folks,
Just a reminder that this is spring break week for Science Jim classes. No classes from March 4 to March 8.
Enjoy the break everyone!
Best,
Jim Mueller
(919) 907-3217
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