Thursday
June 20, 2013

# Posts by Nina

Total # Posts: 384

Science
1.The estimated doubling time for the black sea urchin population is approximately 1.5 years. What is the annual growth rate of the urchin? help please?

Chemistry
A student completes titration by adding 12.0 mL of NaOH(aq) of an unknown concentration to 16.0 mL of 0.15M HCl(aq). what is the molar concentration of the NaOH(aq)?

Social Studies
The last of Wilson's fourteen points called for

Chemistry
Thanks!

Chemistry
Find the molarity of [H+] and [OH-] in the following solutions: a) 0.050 molar NaOH b) 2.09g of calcium hydroxide in 100 mL of water c) 0.875 M H2SO4

Chemistry
That is super helpful, thanks. I missed a two days of class when we learned acids and bases, so I was a bit stuck.

Chemistry
100.0 mL Vinegar (d=1.06g/mL) contains 4% acetic acid. a. How many moles of acid are in 100 mL of vinegar? b. How many mL of 0.11 M NaOH are required to neutralize the vinegar?

Chemistry
Alright, sure. #9. 2H2O -> 2H2 + O2 15g H2O/1 x 1mol/18.02 = 0.832 mol H2O PV=nRT (98.9kPa)(v)=(0.832mol)(8.31 kPaxL/molxK)(290.2K) v=20.29L #11. 12.01g/gC x 100=49.48% 24.27gC/1 x 1mol/12.01g=2.02mol C 1.01g/gH x 100=5.15% 19.61gH/1 x 1mol/1.01g=19.42mol H 14.01g/gN x 100=...

Chemistry
Test corrections :) They're calculations/short answers. I'd just like something to compare answers to or help me get the full answer (all partial credits). Thanks! #9. When water is electrolyzed it produces hydrogen and oxygen. If 10.0% of 150.0g of water is electrolyz...

Chemistry
It's a molar heat reaction lab. 0.07g Mg Mg+2HCl->MgCl2+H2 What is the actual value for the heat of reaction based on the enthalpy's of formation? HfHCl= -118.53 kJ/mole HfMgCl2= -774 kJ/mole

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