Please help. I have no idea how to do these 4 homework problems.
1- How many milliliters of 0.140 M HCl are needed to completely neutralize 42.0mL of 0.106 M Ba(OH)2 solution?
2-How many milliliters of 0.123 M H2SO4 are needed to neutralize 0.250 g of NaOH ?
3-If 55.2 mL of BaCl2 solution is needed to precipitate all the sulfate ion in a 750 mg sample of Na2SO4 , what is the molarity of the solution?
4-If 42.7 mL of 0.218 M HCl solution is needed to neutralize a solution of Ca(OH)2 , how many grams of Ca(OH)2 must be in the solution?
1- How many milliliters of 0.140 M HCl are needed to completely neutralize 42.0mL of 0.106 M Ba(OH)2 solution?
Step 1. Write a balanced equation.
2HCl + Ba(OH)2 ==> BaCl2 + 2H2O
Step 2. How many moles of the base do we have. moles = M x L = 0.106 M x 0.042 L = 0.00445.
Step 3. How many moles of HCl are needed? Use the coefficients in the balanced equation to do this. We have 0.00445 moles Ba(OH)2. It takes twice as much HCl as it does Ba(OH)2; therefore, we must have used 2 x 0.00445 moles HCl = 0.00890 mols HCl.
Step 4. Remember the definition of molarity. M = moles/L. For the HCl we have 0.00890 moles and the molarity is 0.140 M, so solve for L.
L = mols/M = 0.00890/0.140 = 0.0636 L or 63.6 mL.
All of the solution problems are worked the same way. If the problem throws in a solid instead of a solution, just remember that moles = grams/molar mass. After converting into moles, everything is worked the same way. Try it, you'll like it.
How many ml of 9 M HCl are needed to neutralize 0.500 L of 0.350 M NaOH? Given the reaction CH4+2O2=C02+2H2O
No problem! I can help you with these homework problems. I will explain how to approach each problem and guide you through the steps to find the solution.
1- To solve this problem, you need to use the principle of stoichiometry and the concept of molarity. Molarity (M) is defined as the number of moles of solute per liter of solution. You can use the equation:
M1V1 = M2V2
Where M1 is the molarity of the first solution, V1 is the volume of the first solution, M2 is the molarity of the second solution, and V2 is the volume of the second solution.
In this problem, you are given the molarity (0.140 M) and volume (unknown) of HCl and the molarity (0.106 M) and volume (42.0 mL) of Ba(OH)2. You need to find the volume of HCl.
First, convert the volume of Ba(OH)2 from milliliters to liters: 42.0 mL = 0.0420 L
Now, plug the given values into the equation:
(0.140 M)(unknown volume of HCl) = (0.106 M)(0.0420 L)
Solve for the unknown volume of HCl.
2- This problem also involves stoichiometry and molarity. The equation for neutralization between H2SO4 and NaOH is:
H2SO4 + 2NaOH -> Na2SO4 + 2H2O
From the balanced equation, you can see that 1 mole of H2SO4 reacts with 2 moles of NaOH. You can use this information to set up a ratio and calculate the amount of H2SO4 needed.
First, convert the mass of NaOH from grams to moles using its molar mass. (You can find the molar mass of NaOH by adding the atomic masses of sodium, oxygen, and hydrogen.)
Once you have the moles of NaOH, you can determine how many moles of H2SO4 are needed based on the stoichiometry.
Finally, use the equation M1V1 = M2V2 to find the volume of H2SO4, where M1 is the molarity of H2SO4, V1 is the volume of H2SO4, M2 is the molarity of NaOH, and V2 is the moles of NaOH.
3- This problem involves determining the molarity of the BaCl2 solution. The reaction between BaCl2 and Na2SO4 is:
BaCl2 + Na2SO4 -> BaSO4 + 2NaCl
You are given the volume of BaCl2 (55.2 mL) and the mass of Na2SO4 (750 mg). You need to find the molarity.
First, convert the mass of Na2SO4 from milligrams to grams.
Next, calculate the moles of Na2SO4 using its molar mass.
Since the balanced equation shows that 1 mole of BaCl2 reacts with 1 mole of Na2SO4, you can directly determine the moles of BaCl2 needed.
Finally, use the equation M = moles/liters to find the molarity of BaCl2. Convert the volume from mL to L.
4- This problem involves stoichiometry and molarity. The balanced equation between HCl and Ca(OH)2 is:
2HCl + Ca(OH)2 -> CaCl2 + 2H2O
From the balanced equation, you can see that 2 moles of HCl react with 1 mole of Ca(OH)2. Use this information to set up a ratio.
First, calculate the moles of HCl using the equation M = moles/volume. Convert the volume from mL to L.
Since 2 moles of HCl react with 1 mole of Ca(OH)2, you can determine the moles of Ca(OH)2 needed from the moles of HCl.
Finally, calculate the mass of Ca(OH)2 using its molar mass, which you can find by adding the atomic masses of calcium, oxygen, and hydrogen.
I hope this explanation helps you understand how to approach these problems. If you have any further questions or need more assistance, feel free to ask!