General Chemistry Answers

The vapor pressure of water at 25 ºC is 23.8 mmHg. What is the vapor pressure of a solution containing 5.50 g of nonelectrolyte sucrose (MWsucrose= 342 g/mol) in 12.8 g of water (MWwater= 18.0 g /mol) at 25.0 °C

A sample of 0.892 g of potassium chloride (KCl) is dissolved in 54.6 g of water (H2O). Determine the percent mass of KCl in the solution and its molality if the molar mass of KCl is 74.5513 grams

per mole.

CH₄ + 2O₂ = CO₂ + 2H₂O

How many grams of O₂ is needed to produce 37.5 g of CO_2.

30.0 g H2O at an unknown temperature is mixed with 27.0 g of water at 15.8oC in a coffee-cup calorimeter. If the final temperature of the mixture is 29.1oC, what is the initial temperature of the water?

An 88.5 –g piece of iron whose temperature is 78.8 ⁰ C is placed in a beaker containing 244 g of water at 18.8 ⁰ C.

      When thermal equilibrium is reached, what is the final temperature? (Assume no energy is lost to warm the         

       beaker and its surroundings). Cp of water is 4.184 J/g⁰C and the Cp of iron is 0.446 J/g ⁰C.

Write the equilibrium expression, K eq , for each of the following reactions:

1. 2 NO (g) + O 2(g) ⇌2 NO 2(g)

2. 4 HCl (g) + O 2(g) ⇌2 H 2 O (g) + 2 Cl 2(g)

3. NOCl (g) ⇌NO (g) + ½ Cl 2(g)

4. Fe 3+ (aq) + SCN - (aq) ⇌FeSCN 2+ (aq)

5. CaCl 2(s) ⇌Ca 2+ (aq) + 2Cl - (aq)

6. HC 2 H 3 O 2(aq) + H 2 O (l) ⇌ H 3 O + (aq) + C 2 H 3 O 2 - (aq)

7. MgO (s) + CO 2(g) ⇌ MgCO 3(s)

8. C (s) + CO 2(g) + 2Cl 2(g) ⇌ COCl 2(g)

9. Ca 3 (PO 4 ) 2(s) ⇌ 3 Ca 2+ (aq) + 2 PO 4 3- (aq)

10. ZnO (s) + CO (g) ⇌ Zn (s) +CO 2(g)

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DEADLINE : 04/23/2022 11 : 00 PM

How to round off 0.01887006076 moles

Iron can be extracted from haematite, Fe2O3, using either C or CO2 as the reducing agent.

The reactions are shown below.

Fe2O3(s) + 3 C(s) → 2 Fe(s) + 3 CO(g) ΔH = +492.7 kJ /mol

Fe2O3(s) + 3 CO(g) → 2 Fe(s) + 3 CO2(g) ΔH = - 24.8 kJ/mol

Substance S° (J/ K·mol)

Fe2O3 (s) 87.4

Fe (s) 27.3

C (s) 5.7

CO (g) 197.6

CO2 (g) 213.6

Use available data given to:

1. Calculate the minimum temperature at which reduction with carbon is feasible

2. Prove by calculation that reduction with carbon monoxide is feasible at all temperatures

Determine the pH of a 0.20 M NH₃ solution.

1. Determine S for the reaction:

SO3(g) + H2O(l) —> H2SO4(l)

Given: S°(J/K·mol): 256.2 69.9 156.9

2. Calculate S for the reaction

SO2(s) + NO2(g) —> SO3(g) + NO(g)

Given: S°(J/K·mol): 248.5 240.5 256.2 210.6

3. Calculate S at 25C for the reduction of given these absolute entropies:

2PbO(s) + C(s) —> 2Pb(s) + CO2(g)

Given: S°(J/K·mol): 69.54 5.7 64.89 213.6