I need Chemistry help!?

Question

I need someone to help me figure out these questions...please! I need to turn in my Chem hw today.

1. A solution is prepared by dissolving 200.1 g of NaOH (molar mass=40 g/mol) in enough water to make 851 mL of solution. Calculate the molarity of the solution

2. Give the correct formula of ions present when sodium carbonate is dissolved in water?

3. What is the net ionic equation for the reaction of any strong acid with a soluble strong hydroxide base, such as NaOH?

4. What ions are present in a solution of aqueous calcium chloride?

5. What ions are present in a solution of aqueous (NH4)2SO4?

6. What is the net ionic equation for the single replacement reaction Ca (s) + 2 HNO3 (aq)----> H2 (g) + Ca (NO3)2 (aq)

7. What ions are present in an aqueous solution of Iron (III) sulfate?

Thank you!

I am not lazy...I don't know how to do the problems...I said "help" me...I didn't ask for the answers. If someone gives me the steps, I can work them out on my own.

Answer 1

1. Molarity = concentration and it expressed as mol per dm^3
Change the mass to mole and the 851 ml to dm^3. Then find
the ratio of the number of moles to volume in dm^3

2. Soluble ionic compounds breaks up the water molecules in H^+ ions and OH^- ions. Sodium carbonate give Na^+ ions and CO3^2- ions......Other ions that are present are HCO3^- ions called hydrogen carbonate ions. I have found that a solution of sodium carbonate is alkaline: implying that there are more OH^- ions to H^+ ions, due to the formation of HCO^- ions.
3. OH^- (aq) + H^+(aq) ----> H2O (l)
4. H^+ ions (ie. hydrogen ions), OH^- ions (ie. hydroxyl ions),
Ca^2+ calcium ions and Cl^- chloride ions
5. Hydrogen ions, hydroxyl ions. ammonium ions and sulphate ions.
6. Actually the calcium metal reacts with water to give hydrogen gas and calcium hydroxide. At the same time, calcium reacts with nitric acid to give calcium nitrate, water and brown nitrogen dioxide gas.
Hence there is no simple ionic equation for your question
You may want to consider this one:
Ca^0 + 2H^+ + 2OH^- -----> H2(g) + Ca^2+ + 2OH^-
7. Hydrogen ions, hydroxyl ions, iron (III) ions Fe^3+ and sulphate ion SO4^2-

Answer 2

1. Molarity = concentration

formula........concentration = moles/volume in dm^3

so moles of NaOH needs to be worked out first.
moles = mass/molar mass

= 200.1g * 40gmol^-1 = 8004 moles

and if volume = 851mL = 851cm^3 = 0.851dm^3

sooooo concentration =..................





you know what. do it yourself! hahahaha
lazy bugger