A website promoting the use of alternative energy vehicles and hybrid technologies claims that, \"A typical automobile in the USA uses about 500 gallons of gasoline every year, producing about 5 tons of carbon dioxide.\" To determine the truth of this statement, calculate how many tons of carbon dioxide are produced when 500.0 gallons of gasoline are combusted. Assume that the primary ingredient in gasoline is octane, C8H18(l), which has a density of 0.703 g·mL^ –1

HINT:

Generate a balanced chemical equation for the combustion of octane. The reactants will be C8H18+ O2, and the products will be CO2+ H2O. Using the mole ratios from the balanced equation, perform the correct unit conversions to arrive in tons of carbon dioxide. Note that : 1 gallon = 3785.4 cm3 1 lb = 453.6 g

A voltaic cell employs the following redox reaction:
Sn2+(aq)+Mn(s)→Sn(s)+Mn2+(aq)
Calculate the cell potential at 25 ∘C under each of the following conditions.

A) Standard condition

B) [Sn2+]= 1.64×10⁻² M ; [Mn2+]= 2.25 M

C) [Sn2+]= 2.25 M ; [Mn2+]= 1.64×10⁻² M

An empty 5.00-L flask is charged with 0.250 g of pure H2S(g), at 25 ∘C.

What is the initial pressure of H2S(g) in the flask? 3.59*10^-2 atm

In addition to the H2S already present in the flask, solid NH4HS is added until there is excess unreacted solid remaining.

a) What are the partial pressures of NH3 and H2S at equilibrium, that is, what are the values of PNH3 and PH2S, respectively?

b)What is the mole fraction, χ, of H2S in the gas mixture at equilibrium?

c)What is the minimum mass of NH4HS that must be added to the 5.00-Lflask when charged with the 0.250 g of pure H2S(g), at 25 ∘C to achieve equilibrium? Express your answer numerically in grams.

Insoluble PbBr2(s) precipitates when solutions of Pb(NO3)2(aq) and NaBr(aq) are mixed.

Pb(NO3)2(aq) + 2 NaBr(aq) → PbBr2(s) + 2 NaNO3(aq) ΔrH° = ?

To measure the enthalpy change, 200. mL of 0.75 M Pb(NO3)2(aq) and 200. mL of 1.5 M NaBr(aq) are mixed in a coffee-cup calorimeter. The temperature of the mixture rises by 2.44 °C. Calculate the enthalpy change for the precipitation of PbBr2(s), in kJ/mol. (Assume the density of the solution is 1.0 g/mL, and its specific heat capacity is 4.2 J/g ∙ K.)

From the enthalpies of reaction H2(g)+F2(g)→2HF(g)ΔH=−537kJ C(s)+2F2(g)→CF4(g)ΔH=−680kJ 2C(s)+2H2(g)→C2H4(g)ΔH=+52.3kJ calculate ΔH for the reaction of ethylene with F2: C2H4(g)+6F2(g)→2CF4(g)+4HF(g)

If 1.5 moles of hexane ( ) combust to completion: 6 14 C H

2.1 How many moles of CO2 would we have at the end of the reaction? [1]

2.2 How many moles of H2O would we have? [1]

2.3 How many moles of O2 would be consumed? [1]

2.4 What mass of oxygen would this correspond to? [2]

2.5 If after complete combustion, it is found that the combustion product contains 10% (mole) of oxygen. What was the mass fraction of oxygen in the mixture before combustion? [3]

NO OTHER DATA PROVIDED

4. A give soil has a CEC of 12.50 cmol of charge per kg of soil. If 70%, 15%, 10% and 5% of the CECis occupied by Ca+2, K+1, Mg and Na+1 , respectively, calculate the weight (grams) of Ca, K, Mg and Na in the soil.

5. A given soil contains the following colloids: 1.0% humus (CEC=200), 30% kaolinite (CEC=5), 5%smectite (montmorillonite) (CEC=80), 10% illite (CEC=20), 5% mica (CEC=70) and 49% sesquioxides (CEC=2). Calculate the CEC of the soil? Which colloids contributed the most and which contributed the least? (All CEC are in molc/kg soil).

6. Calculate the amount of pure CaCO3that could theoretically neutralize the H+ in one-year acid rain if a 1-hectare (ha) site received 200 mm of rain per year and the average pH of the rain was 5.0.

7. Calculate the pH and pOH of a soil with the following H+ concentrations: (a) 0.0000001M (b) 0.00001M (c) 0.005M? Which soil is relatively most acidic? Most basic?

8. Determine the calcium carbonate equivalent (CCE) of the following compounds: (amount that has the same neutralizing value as 100 g pure CaCO3) (a) KOH (b) Mg(OH)2 (c) and CaMg(CO3)2.

9. How many grams of limestone with a CaCO3 equivalent of 100% would you need to apply to an acidic soil with 85% exchangeable Al saturation to reduce it to 10%? The CEC of the soil is 12.5cmolc/kg.

10. How many grams of gypsum (CaSO4.2H2O) would you need to reclaim a sodic soil with an exchangeable sodium percentage (ESP) of 80% to reduce to it to 50%? The CEC of the soil is 12.5cmolc/kg.

Calculate E∘cell for each of the following balanced redox reactions. Are the reactions spontanous?

A) 2Cu(s)+Mn2+(aq)→2Cu+(aq)+Mn(s)

B) MnO2(s)+4H+(aq)+Zn(s)→Mn2+(aq)+2H2O(l)+Zn2+(aq)

C) Cl2(g)+2F−(aq)→F2(g)+2Cl−(aq)

What are some real-life applications of substitution reactions (SN1 & SN2) and elimination reactions (E1 & E2)? Please be specific and detail.

2CH₄ + 4Cl₂ = 2CHCL₃ + 2HCL

1) If 5.5 CH₄ react with 27.4 g CL₂ what is the limiting reactant and what mass of HCl will form? (I can find the LR but I have problems with finding the mass of HCL)

2) If for the above reaction, the theoretical yield of CH₃Cl is 7.2g and the actual yield of HCl is 3.2 g, what is the percent yield?

Determine the limiting reactant (LR) and the mass (in g) of nitrogen that can be formed from 50.0 g N2O4 and 45.0 g N2H4. Some possibly useful molar masses are as follows: N2O4 = 92.02 g/mol, N2H4 = 32.05 g/mol.

            N2O4(l) + 2 N2H4(l) → 3 N2(g) + 4 H2O(g)

1. A fossil is found to have a 14C level of 87.0% compared to living organisms. How old is the fossil?

(answer in years)

2.Iodine-131 is a radioactive isotope. After 3.00 days, 77.2% of a sample of 131I remains. What is the half-life of 131I?

(answer in days)