1. E

    Simple solution question

    Hi all, I have a very simple problem but for some reason I am having trouble with it. I need to dope 0.5g of solid powder with element X to a concentration of 500ppm. I have a solution containing 1000ppm element X. How many mL of this solution do I need to add to the 0.5g of powder in order to...
  2. I

    Can you help me with these problems?

    Hi everyone,I just wanted to ask if you can help me with some of the problems that I have for homework.Although they are simple to most people, to me and some of my classmates , they are not, primarily because of our teacher.Thank you in advance. 1.How many moles of Calcium chloride hexahydrate...
  3. K

    Is there any simple test for air quality / components

    I'd like to prepare a simple test to check if the air flowing out from the air-conditioner contains any harmful materials / chemicals, or at least, if the air is pure outdoor air. The air -conditioner was probably handled with improper method by improper people. I'd like to know if there is any...
  4. K

    simple entropy Q HELP!

    Hi guys! This is my first time posting here. I'm currently studying chemistry and have questions about entropy. First, I want to check a few things that I know of entropy. Please correct me if I know it wrong. -it increases when solid->liquid->gas -it increases when breaking the bond -it...
  5. T

    Simple Change in Molar Volume Question

    Hi, The question states: "Calculate the change in molar volume for the reaction of corundum (Al_2O_3) in liquid water to from gibbsite (Al(OH)_3). My question would be, is when I look at the table that was provided, (Al(OH)_3) is listed in aquas form but does not list a molar volume. But if I...
  6. B

    simple redox chemistry question

    question: I don't get it why isn't the answer just -0.68V, as it is the reverse reaction of the reduction of O2 to H2O2 which is the oxidation of H2O2 to O2 which is what the question wants?
  7. R

    Potassium Bromide. Where does it come from?

    Potassium Bromide's compound formula is KBr, right..? I don't understand how to explain where it came from, because it's obviously not naturally made. How is it made? I'm confused.. I've read that it's made from some carbonate and iron and it's drained out and lsdkjfsldkfj sl I don't know...
  8. C

    simple chemistry question

    Two astronauts on the moon use an equal-arm balance to find the mass of a specimens of a moon rock; the specimen has a mass of 35.83 g. When the astronauts return to earth and mass the specimen again, will they find the mass of the rock on the earth to be more, less or equal to the 35. 83 g they...
  9. M

    Simple # of Atoms Calculation

    Hi guys, Just a bit of background on me: I completed chemistry in high school and did pretty good, but then when I went to university I didn't take any chem courses for a year. This coming fall I'm going to be enrolled in an introductory university chem course, so I'm doing some prep work now...
  10. M

    A simple question, not the exercise?

    A 50.0-mL sample of 0.400 M copper(II) sulfate solution at 23.35°C is mixed with 50.0 mL of 0.600 M sodium hydroxide solution, also at 23.35°C, in the coffee-cup calorimeter of Exercise 6.1. After the reaction occurs, the temperature of the resulting mixture is measured to be 25.23°C. The...
  11. I

    Need help with simple question on a lab.

    So we did a lab in school on what is the effect of flour on slime which is mixed with borax and glue on the length it can be stretched. I have completed the experiment and found out it stretched much longer than the control variable with is normal slime without flour. I finish writing my...