Chemistry 2006/ 2007 Club***

Nursing Students Pre-Nursing

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I am starting Chem II this semester. Anyone want to start a club??? :rolleyes:

Specializes in LTC, subacute CNA.

I've got my first chemistry exam on Monday! I've been studying my butt off. *crosses fingers*

Good luck on your test on Monday! I had my first test a week ago and made an 85. Because most of the class failed that test, the professor allowed a retest for a higher grade. He will take the higher of the 2 test scores. So I had the retest yesterday. I need that A so badly. Nursing school is getting so hard to get into down here!

Happy studying!

I thought I had this all down pat, but now I'm confused about some homework problems. I am able to solve them (problem a was a *beast*) but not figure out the sig figs.

Also, when I am solving a problem with multiple steps, do I factor in the sig figs during the steps, or do I wait until the end? Example, I need 3 sig figs but in the first step of the problem my answer on the calculator has 8 figures. Do I carry those 8 figures over to the second part of the problem, or do I first round them to 3 sig figs? Either way will give me a slightly different final answer.:confused:

a) A sample of metal with a mass of 500.0 g is heated to 225.0 degrees C and then dropped into a 400.0 mL sample of water. The water's temperature is initially 24.0 degrees C and its final temperature (after the metal is dropped into it) is 36.0 degrees C. What is the specific heat of the metal in J/gC?

b) The amount of Vitamin C in an 8.000 fl oz. glass of orange juice is 0.5200 mg. How many liters of orange juice contain 25.0 g of Vitamin C? (1.0000 fluid oz = 29.573 ML measured)

I thought I had this all down pat, but now I'm confused about some homework problems. I am able to solve them (problem a was a *beast*) but not figure out the sig figs.

Also, when I am solving a problem with multiple steps, do I factor in the sig figs during the steps, or do I wait until the end? Example, I need 3 sig figs but in the first step of the problem my answer on the calculator has 8 figures. Do I carry those 8 figures over to the second part of the problem, or do I first round them to 3 sig figs? Either way will give me a slightly different final answer.:confused:

a) A sample of metal with a mass of 500.0 g is heated to 225.0 degrees C and then dropped into a 400.0 mL sample of water. The water's temperature is initially 24.0 degrees C and its final temperature (after the metal is dropped into it) is 36.0 degrees C. What is the specific heat of the metal in J/gC?

b) The amount of Vitamin C in an 8.000 fl oz. glass of orange juice is 0.5200 mg. How many liters of orange juice contain 25.0 g of Vitamin C? (1.0000 fluid oz = 29.573 ML measured)

after the first unit my instructor doesn't worry about significant figures, but if I remember correctly we are suposed to do all the work first then figure significant figures. As far as your problems I will have to look them up it was 2 units ago we did joules and Specific heat lol I'll look though and see if I can figure it out.

Specializes in LTC, subacute CNA.

Okay, I had my chem test a few days ago. It was my first real test in 6 years since my first round of college. I know for sure that I got one question wrong. A simple conversion and I can't figure out for the life of me how to get the right answer. Here it is:

d= 3.12g/mL. Convert it to kg/L. I kept getting 3.12kg/L.:confused: I tried solving the problem several different ways. It was like being in a bad dream! Anyone up to solving that one for me? I'm sure I am just missing something obvious.

Fortunately I did well on everything else. Or so I hope. I'll find out when I get the test back next week.

Okay, I had my chem test a few days ago. It was my first real test in 6 years since my first round of college. I know for sure that I got one question wrong. A simple conversion and I can't figure out for the life of me how to get the right answer. Here it is:

d= 3.12g/mL. Convert it to kg/L. I kept getting 3.12kg/L.:confused: I tried solving the problem several different ways. It was like being in a bad dream! Anyone up to solving that one for me? I'm sure I am just missing something obvious.

Fortunately I did well on everything else. Or so I hope. I'll find out when I get the test back next week.

How many Kg in a gram?

How many liters in a ml? get your conversion factors and work the problem that way

Hello all...My problem is that we are always step ahead in the lab then in the class (or two steps)...so I am stuck with some problems....They are similar to one (i bleieve) on this page but I just can not get it...

1. If 12 moles of Al2O3 are produced, how many moles of aluminum reacted?

2. If 75 g of oxygen react, how many grams of aluminum are required?

I belive i shoudl findmolar mass for Aj2O3 (101.96 g/mol) and i shoud do the ratio but I am not sure is that correct or not....Thanks all...

In order to help you with this problem, we need to see the complete balance equation. What equation were these problems asked with?

In order to help you with this problem, we need to see the complete balance equation. What equation were these problems asked with?

sorry;;;

4Al+3O2=2Al2O3

ok, in the first problem I am getting the following:

4Al + 3O2 ----> 2Al2O3

1. If 12 moles of Al2O3 are produced, how many moles of aluminum reacted?

12 mol of Al2O3 X 4 mol Al/2mol Al203 = 24 mol Al

2. If 75 g of oxygen react, how many grams of aluminum are required?

In this problem you need to go from g O2 ---> mol O2 ---> mol Al --> g Al

75 g O2 x 1 mol O2/32.00 g O2 x 4 mol Al/3 mol O2 x 26.98 Al/1 mol Al = 84 g Al

Please someone double check me and I hope this helps.

Specializes in LTC, subacute CNA.
How many Kg in a gram?

How many liters in a ml? get your conversion factors and work the problem that way

That's how I was doing the problem, and I still keep getting 3.12 kg/L as my answer. *scratches head*

3.12g * 1kg * 1000mL divided by

1mL 1000g 1L

=3.12kg/L

I also tried it as .001kg/g and .001mL/L

ok, in the first problem I am getting the following:

4Al + 3O2 ----> 2Al2O3

1. If 12 moles of Al2O3 are produced, how many moles of aluminum reacted?

12 mol of Al2O3 X 4 mol Al/2mol Al203 = 24 mol Al

2. If 75 g of oxygen react, how many grams of aluminum are required?

In this problem you need to go from g O2 ---> mol O2 ---> mol Al --> g Al

75 g O2 x 1 mol O2/32.00 g O2 x 4 mol Al/3 mol O2 x 26.98 Al/1 mol Al = 84 g Al

Please someone double check me and I hope this helps.

Thank you...This make sence....It is so add to have Lab prior to class so we are doing lab before we acctualy learn it. Thanks again...

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