All Chemistry Questions & Answers

chem question	could you please help me with this question: how many grams of water must be added to 200 ml of NaOH solution in order to have a solution with a specific gravity of 1.157, 13.55%? (Specific gravity= 1.32, 28.83%).
How to convert wt% MgCO3 to mole% MgCO3	I have geochemistry data for limestone samples consists of oxides and REE. I want to find out the mole% MgCO3 for the samples. I understand that I can use conversion factor of 3.4683 to convert MgO wt% to MgCO3 wt%. But from there I don't know how to proceed.
Is this the correct oxidation numbers for H and O in hydrogen peroxide H2O2; H 1+, O 1- . Why or why not ?	Yes H is +1 and O is -1 is peroxides so these oxidation numbers are correct .
What is the oxidation number of nitrogen in nitric acid,HNO3 ?	Nitrogen has +5 oxidation number in HNO3
Is the reaction 2Al(s) + 3Cl 2 (g) ----> 2AlCl 3 (s) can be considered as the redox reaction ?	Yes, since Al is underging an oxidation and Cl is undergoing reduction .
Does a reducing agent oxidized or reduced in a oxidation-reduction reaction ?	A reducing agent oxidizes during a oxidation -reduction reaction
When 0.150 L of 0.10 M lead (II) nitrate and 0.100 L of 0.20 M sodium chloride are mixed? For PbCl 2 , K sp = 1.2 x10 - 5	Q>Ksp, so PbCl2 does precipitate.Eq shifts to the left .
When 0.150 L of 0.10 M lead (II) nitrate and 0.100 L of 0.20 M sodium chloride are mixed? For PbCl 2 , K sp = 1.2 x10 - 5
Mercury(I) chloride, Hg2Cl2.It has a Ksp equal to 1.3 × 10 − 18.What is the solubility of Hg2Cl2 ?	6.88 × 10-7M
0.133 mg of silver bromide AgBr will dissolve in 1.00 L of water. What is the value of Ksp for AgBr?	Ksp= 5.02 × 10-13