# Chemistry Math Help!

1. Sep 8, 2006

1) Vanillin (used to flavor vanilla ice cream and other foods) is the substance whose aroma the human nose detects in the smallest amount. The threshold limit is 2.0 10-11 g per liter of air. If the current price of 50. g of vanillin is $112, determine the cost to supply enough vanillin so that the aroma could be detected in a large aircraft hangar with a volume of 3.0 107 ft3. (Enter your answers in units of dollars and two decimal places.) 2) The total volume of seawater is 1.5 1021 L. Assume that seawater contains 3.1 percent sodium chloride by mass and that its density is 1.03 g/mL. Calculate the total mass of sodium chloride in kilograms and in tons. (1 ton = 2000 lb; 1 lb = 453.6 g) 3) Chalcopyrite, the principal ore of copper (Cu), contains 34.63% Cu by mass. How many grams of Cu can be obtained from 5.80 103 kg of the ore? 4) The density of sulfuric acid in a certain car battery is 1.41 g/mL. Calculate the mass of 165 mL of the liquid. 5) The volume of a room is 2.07 108 dm3. What is the volume in m3? Ive done about 40 out of 50 so far and these are the ones I got stuck on. 2. Sep 8, 2006 ### dmoravec welcome to the forum! the rules are that you need to show some work/ideas on the problems for us to help you 3. Sep 8, 2006 ### ticklemedammit Thanks What do you mean by showing some work/ideas? 4. Sep 8, 2006 ### dmoravec well lets start with the first problem, how would you first attempt this problem? Hint: Figure out what quantities you need to finish the problem and how you might be able to get them from the values you have. 5. Sep 8, 2006 ### ticklemedammit Sorry but I dont even know where to begin, which is why I turned to an forum for help. 6. Sep 8, 2006 ### dmoravec ok, i'll try and walk you though the first one. 1) Vanillin (used to flavor vanilla ice cream and other foods) is the substance whose aroma the human nose detects in the smallest amount. The threshold limit is 2.0 10-11 g per liter of air. If the current price of 50. g of vanillin is$112, determine the cost to supply enough vanillin so that the aroma could be detected in a large aircraft hangar with a volume of 3.0 107 ft3. (Enter your answers in units of dollars and two decimal places.)

The first thing we want to figure out is the amount of vanillin that we need to fill the entire hanger. Unfortunatly the units of volume for the hanger are in feet^3 and not liters... a quick look online tells me that 1ft^3=28.32L. So to convert the volume of the hanger to liters it is 3.0 * 10^7 ft^3 * 28.32L = 8.5 * 10^8 L.

Now we can use the threshold limit of 2.0 * 10^-11 g/L of air. We have 8.5 * 10^8 L so we will need 2.0*10^-11 g/L * 8.5 * 10^8 L = X g of Vanillin... once we have that the cost can be figure out.
Does this help at all?

7. Sep 8, 2006

### Hootenanny

Staff Emeritus
8. Sep 8, 2006

### ticklemedammit

Thanks let me try to work it out now

9. Sep 8, 2006

### ticklemedammit

Sorry about that, feel free to move it over there.

10. Sep 8, 2006

### Hootenanny

Staff Emeritus
Don't worry about it, just letting you know . I don't have the privileges to do so, but I'm sure a mentor will move it in due course.

11. Sep 8, 2006

### ticklemedammit

Okay I figured out number 1