Help please! I can't solve any of these, would someone be as kind as to show me the answers?
How many moles of NaHCO3 are in a 125.0 g sample of the compound?
3. How many moles are in 6.73 x 1024 water molecules?
4-5. AgBr, a chemical used in photography can be made with this reaction:
2AgNO3 + CaBr2 „³ 2AgBr + CaN2O6
4. AgNO3 is very expensive, so in making AgBr, you want to be sure this reactant is all used up. If a chemist starts with 15.0 g of AgNO3, how many grams of CaBr2 must be added to use up all of the AgNO3?
5. How many moles of CaN2O6 are produced when 46.8 g or AgNO3 react?
6. DDT, an insecticide banned in the US, has the formula C14H9Cl5? Find its percent composition.
How many moles of NaHCO3 are in a 125.0 g sample of the compound?
moles = grams/molar mass
3. How many moles are in 6.73 x 1024 water molecules?
1 mole of anything contains 6.02 x 10^23 anythngs; therefore, 1 mole of water molecules will contain 6.02 x 10^23 molecules of water. So convert t moles by .....
4-5. AgBr, a chemical used in photography can be made with this reaction:
I don't know what you've had in class to answer this question but AgBr can be made in a number of different ways. One way is
NaBr + AgNO3 ==> AgBr + NaNO3.
Number 4 answer is 8.81
Sure! I can help you solve these questions step by step.
1. How many moles of NaHCO3 are in a 125.0 g sample of the compound?
To find the number of moles, you need to use the molar mass of NaHCO3. The molar mass of NaHCO3 is calculated by adding up the atomic masses of its constituent elements: Na (22.99 g/mol), H (1.01 g/mol), C (12.01 g/mol), and O (16.00 g/mol).
Molar mass of NaHCO3 = 22.99 + 1.01 + 12.01 + (3 x 16.00) = 84.01 g/mol
Now, divide the mass of the sample by the molar mass to get the number of moles:
Number of moles = 125.0 g / 84.01 g/mol
2. How many moles are in 6.73 x 10^24 water molecules?
To calculate the number of moles from the number of water molecules, you need to use Avogadro's number, which is 6.022 x 10^23 molecules/mol.
Number of moles = (6.73 x 10^24 water molecules) / (6.022 x 10^23 molecules/mol)
3. AgNO3 is very expensive, so in making AgBr, you want to be sure this reactant is all used up. If a chemist starts with 15.0 g of AgNO3, how many grams of CaBr2 must be added to use up all of the AgNO3?
To determine the mass of CaBr2 required, we need to use the stoichiometric ratio from the balanced equation. From the balanced equation:
2 moles AgNO3 : 1 mole CaBr2
First, convert the mass of AgNO3 to moles using its molar mass:
Number of moles of AgNO3 = 15.0 g / molar mass of AgNO3
Then, use the stoichiometric ratio to find the moles of CaBr2 required:
Number of moles of CaBr2 = (Number of moles of AgNO3) / 2
Finally, convert the moles of CaBr2 to grams using its molar mass:
Mass of CaBr2 = (Number of moles of CaBr2) x molar mass of CaBr2
4. How many moles of CaN2O6 are produced when 46.8 g of AgNO3 reacts?
Similar to the previous question, you need to use the stoichiometry from the balanced equation to find the moles of CaN2O6 produced.
First, convert the mass of AgNO3 to moles using its molar mass:
Number of moles of AgNO3 = 46.8 g / molar mass of AgNO3
Then, use the stoichiometric ratio to find the moles of CaN2O6 produced:
Number of moles of CaN2O6 = (Number of moles of AgNO3) x (1 mole CaN2O6 / 2 moles AgNO3)
5. DDT, an insecticide banned in the US, has the formula C14H9Cl5. Find its percent composition.
To find the percent composition of an element in a compound, divide the molar mass of that element by the molar mass of the whole compound and multiply by 100.
Calculate the molar mass of C14H9Cl5 by adding the atomic masses of carbon (C), hydrogen (H), and chlorine (Cl).
Molar mass of C14H9Cl5 = 14 x atomic mass of C + 9 x atomic mass of H + 5 x atomic mass of Cl
Then, divide the molar mass of each element by the molar mass of the compound, and multiply by 100 to get the percent composition.