Need Help Please! Thank you. 1) 25.0 g of sodium hydroxide is neutralized with s

Question

Need Help Please! Thank you.

1) 25.0 g of sodium hydroxide is neutralized with sulfuric acid. How many grams of sodium sulfate can be formed?

2) What mass of oxygen, in grams can be prepared from 24.9 g H2O2?

H2O2 --> H2O + O2 (not balanced)

4) What is the mass percent of CaCO3 present if a 4.38 g piece of chalk yields 1.31 g CO2, when it reacts with excess HCl?

5) A particular 100-octance aviation gasoline used 1.00 mL of tetraethyl lead, (C2H5)4Pb, of density 1.66 g/mL, per liter of product. This compound is made as follows: C2H5Cl + NaPb --> (C2H5)4Pb + NaCl + Pb

How many grams of ethyl chloride, C2H5Cl, are needed to make enough tetraethyl lead of 1 L of gasoline/?

6) A 1.2048 g impure sample of Na2CO3, is dissolved and allowed to react with a solution of CaCl2. The resulting CaCo3, after precipitation, filtration and drying was found to mass 1.0262 g. Assuming that the impurities do not contribute to the mass of the precipitate, calculate the precentage purity of the Na2CO3.

Na2CO3 + CaCl2 --> CaCO3 + NaCl (not balanced)

Explanation / Answer

1) 25.0 g of sodium hydroxide is neutralized with sulfuric acid. How many grams of sodium sulfate can be formed?

2NaOH + H2So4 --------> Na2So4 + H2O

2 mole of NaOH react with H2SO4 to form 1 mole of Na2SO4

2*40g of NaOH react with H2So4 to form 142g of Na2So4

25 g of NaOH react with H2So4 to form = 142*25/2*40 = 44.375 g of Na2SO4

2) What mass of oxygen, in grams can be prepared from 24.9 g H2O2?

H2O2 --> H2O + O2 (not balanced)

2H2O2 --> 2H2O + O2

2 moles of H2O2 decomposes to give 1 mole of O2

2*34g of H2O2 decomposes to gives 32g of O2

24.9g of H2O2 decomposes to gives = 32*24.9/2*34 = 11.71 g ofO2

4) What is the mass percent of CaCO3 present if a 4.38 g piece of chalk yields 1.31 g CO2, when it reacts with excess HCl?

CaCo3 + 2HCl -------> CaCl2 + Co2 + H2O

1 mole of Co2 produced from 1 mole of CaCO3

1*44g of CO2 produced from 100g of CaCo3

1.31g of Co2 produced from = 100*1.31/44 = 2.97g

mass percentage of CaCO3 = 2.97*100/4.38 = 67.8% >>>> answer

5) A particular 100-octance aviation gasoline used 1.00 mL of tetraethyl lead, (C2H5)4Pb, of density 1.66 g/mL, per liter of product. This compound is made as follows: C2H5Cl + NaPb --> (C2H5)4Pb + NaCl + Pb

How many grams of ethyl chloride, C2H5Cl, are needed to make enough tetraethyl lead of 1 L of gasoline/?

4C2H5Cl + 4NaPb --> (C2H5)4Pb + 4NaCl + 3Pb

mass of traethyl lead is = volume * density

                                   = 1000*1.66 = 1660g

1 mole of (C2H5)4Pb produced from 4 moles of C2H4Cl

323.45g of (C2H5)4Pb produced from 4*63.5g of C2H4Cl

1660g of (C2H5)4Pb produced from = 4*63.5*1660/323.45 = 1303.57g of C2H5Cl

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