Chemistry Answers

How many methane molecules will be removed?

Calculate the boiling point and freezing point of a solution containing 478g of ethylene glycol in 3202g of water.

b) With proper examples draw a distinction between mathematical and econometric models?

The amino acid methionine, which is essential in human diets, has the molecular formula C5H11NO2S. Determine (a) its molecular mass; (b) the number of moles of H atoms per mole of methionine; (c) number of grams of C per mole of methionine; (d) the number of C atoms in 9.07 mol methionine

Cisplatin or Platinol has a chemical PtCl2(NH3)2 that is used in the treatment of certain cancers. Calculate (a) the amount (mol) of compound in 285.3 g of cisplatin; (b) the number of hydrogen atoms in 0.98 mol of cisplatin.

B. Hess’s Law

1. Using Hess’ Law and the following information calculate the heat of formation of the plant hormone ethylene, C2H4 in the equation: 2 C(s) + 2 H2(g) → C2H4(g)

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2. Calculate the value of Ho/kJ for the following reaction using the listed thermochemical equations:

P4O10(g) + 6 PCl5(g) 10 Cl3PO(g)

1/4 P4(s) + 3/2 Cl2(g) --> PCl3(g) ∆Ho = -306.4

P4(s) + 5 O2(g) --> P4O10(g) ∆Ho= -2967.3

PCl3(g) + Cl2(g) --> PCl5(g) ∆Ho= -84.2

PCl3(g) + 1/2 O2(g) --> Cl3PO(g) ∆Ho = -285.7

First Law of Thermodynamics and Calorimetry (5 points each)

A gas system with constant pressure has change in internal energy of 440 J. Heat was lost to the surroundings and 250 J work was done to the surroundings as well. How many calories of heat was lost?

0.315 moles of butane (C4H10) was burned in a copper calorimeter containing 4500 g of water. The calorimeter weighs 2,500 g. The temperature was observed to increased by 3.15 °C. Calculate the molar heat of combustion of butane (HEAT OF COMBUSTION PER MOLE). The specific heat of copper and water are 0.386 J/g. °C and 4.18 J/g. °C respectively.

A 45-g silver spoon (specific heat 0.233 J/g °C) at 25 °C is placed in 180 g of coffee at 85 °C and the temperature of the two become equal. What is the final temperature when the two become equal? The coffee has specific heat of 5.12J/g. °C.

how many moles of water can be produced from 58 moles of C6H14

1.     Why is it difficult to test the presence of chloride in organic compounds than in inorganic ones like hydrochloric acid? 

Write the electron configuration for magnesium (A=12) and potassium (A=19). Draw their orbital diagrams.