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# Chemistry

## Discover

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### Options other than Yahoo Answers?

I see that Yahoo is shutting down Yahoo!answers at the beginning of May. For those of you who answer questions here, what are other options for asking and answering questions like this? I've actually enjoyed spending time here and helping people deal with Chemistry questions. Where else can I do something similar?

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### is there a way to melt sand using a oven?

Yes or no without it being a fire hazard possible yes no

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### How to remove glue / adhesive residue from metal?

Have you tried WD-40 (the miracle chemical?)

https://wd40.co.uk/

Acetone, petrol, dichloromethane are all the same class of chemical. I suspect your "glue remover" is more of the same (ethanol + C12-C14 alkanes).  If they haven't worked so far, they're not going to do it.

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### A sample of gas has an initial pressure of 1.50 atm at a volume of 3.40 L at a temperature of 20.0°C. ?

(3.40 L) / (20.0 + 273.15) K x (20.0 + 10.0 + 273.15) K x (1.50 atm / 2.50 atm) =

2.11 L

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### If our state was represented by just one food, what would it be?

Granola. Fruits, nuts, and flakes.

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### one mole of a gas occupies 22.4 L at 0°C and 760 mm Hg. ?

(22.4 L/mol) x (2.00 mol) = 44.8 L

(760 mmHg) x (44.8 L / 3.00 L) x (25 + 273) K / (273 K) = 12389 mmHg =

12400 mmHg

[Kenny B: Knowing the molar volume relieves you from knowing any value for R.]

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### What does phenolphthalein do?

It turns color to indicate the pH of a liquid solution.  It's also pretty good for weeding people out of spelling bees.

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### Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen.  ?

2 Mg + O2 → 2 MgO

(4.99 g Mg) / (24.30506 g Mg/mol) = 0.20531 mol Mg

(8.79 g O2) / (31.99886 g O2/mol) = 0.27470 mol O2

0.20531 mole of Mg would react completely with 0.20531 x (1/2) = 0.102655 mole of O2, but there is more O2 present than that, so O2 is in excess and

Mg is the limiting reactant.

(0.20531 mol Mg) x (2 mol MgO / 2 mol Mg) x (40.3044 g MgO/mol) x (84.5 / 100) =

6.99 g MgO (product)

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### What's stronger than acid?

Acids aren't all equally powerful, they come in different concentrations.  That's the important thing.  One can even drink weak acids but drinking concentrated acids would cause a painful death.  It's like asking how long is a piece of string?

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