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May 6, 2016

Homework Help: chemistry

Posted by Andy on Monday, September 21, 2009 at 2:39pm.

If 1.20 grams of sodium metal are reacted with 4.00mL of water, how many grams of NaOH will be produced (density of water= 1.00g/mL)
• chemistry - DrBob222, Monday, September 21, 2009 at 3:54pm

2Na + 2H2O ==> 2NaOH + H2

Technically, this is a limiting reagent problem. First, write and balance the equation. I have done that above.

2a. Convert grams Na metal to moles. moles = grams/molar mass.
b. Convert grams H2O to moles.

3a. Using the coefficients in the balanced equation, convert moles Na to moles H2 gas.
b. Do the same for moles H2O.
c. You will get two answers, of course, for moles H2 produced. Obviously, both can't be right. The correct answer is the smaller number and the material producing that result is the limiting reagent. I believe you will find the limiting reagent to be Na.

4. Convert moles from step 3c (for the limiting reagent) to grams.
grams = moles x molar mass.
Check my thinking.