1) You are given a solid hydrate. You dry and weigh a sample
tube. You put in the hydrate and reweigh.
You heat the tube and contents to drive off any water then cool and
reweigh.
You obtain the following fictional data:
Mass of sample tube and hydrate | 37.9143 g |
Mass of sample tube and hydrate after heating and cooling | 36.8824 g |
Mass of empty sample tube | 35.6254 g |
Molecular weight of the anhydrous salt | 112.0 g/mol |
Calculate:
Mass of hydrate weighed out | _______________ g | (a) |
Mass of water lost after heating | _______________ g | (b) |
Per cent water in the hydrate | _______________ % | (c) |
Moles of water lost during heating | _______________ mol | (d) |
Moles of anhydrous salt remaining after heating | _______________ mol | (e) |
Ratio-moles of water per mole of anhydrous salt | _______________ | (f) |
Report this ratio (f) as a single number to two decimal places, e.g. the ratio of 2.00 mole water and 1.50 mol salt is 1.33
In: Chemistry
Calculate the amount of ATP in kg that is turned over by a resting human every 24 hours. Assume that a typical human contains ~50g of ATP (Mr 505) and consumes ~8000 kJ of energy in food each day. The energy stored in the terminal anhydride bond of ATP under standard conditions is 30.6 kJmol-1. Assume also that the dietary energy is channeled through ATP with an energy transfer efficiency of ~50%.
In: Chemistry
Consider a gas phase reaction, 2A+B −↽−⇀− 3C+2D. When 1.00 mol A and 2.00 mol B, and 1.00 mol D were mixed and allowed to come to equilibrium at 25◦ C and ptotal = 1.0 bar, the resulting mixture contained 0.90 mol C. Calculate (a)partial pressures of each at equilibrium, (b) Keq, and (c) ∆rG.
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two solutions can be found on either side of a semi-permeable membrane. a 4.0m sucrose solution is found on the left side and a 2.0m Nacl solution is found on the right side. which direction will the solvent flow?
Also what would happen if it was 2.0m nacl on left and 4.0m sucrose on right ? what if it was 2.0nacl and 2.0m sucrose ?
please explain thanks
In: Chemistry
Plastic cup C
Mass of cup, water, and stirrer: 57.24g
Mass of sodium bicarbonate: 2.02g
Mass of citric acid: .76g
Total mass: 60.02g
Mass of cup, the solution, and stirrer after reaction: 59.53g
Difference: 0.49g
H3C6H5O7(aq) + 3NaHCO3(aq) --->Na3C6H5O7(aq) + 3H2O(l) + 3CO2(g)
1)Determine which reactant is the limiting reactant in the plastic up C. Describe your reasoning
2) Calculate the theoretical yield of carbon dioxide in plastic cup C
3) Calculate the percentage yield in plastic cup C
In: Chemistry
You have a solution that is 0.25M Ca2+ and .18M Ag+. You begin to add CO32- (carbonate ion) to form CaCO3 , and Ag2CO3. Which will precipitate first? Second?
What is the concentration of the first ion at the point when the second begins to precipitate?
What percentage of the first ion has been removed?
There three questions here.
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In: Chemistry
You determined the theoretical yield if 0.5 moles of zinc is used to form ZnI2. Determine the percent yield if 515.6 g of product is recovered.
___ Zn + __I2 → ___ZnI2
In: Chemistry
A 10.45-m3 sample of gas (310K, 745mmHg pressure) was passed through a series of traps that removed teh water from the gas. The gas that came out was found to be at 780mmHg pressure and 273K. Its volume was 8.73-m3. What was the percentage of water vapor (v/v) in the original sample of gas? Assume ideal behavior for all gasous compounds.
In: Chemistry
A student is asked to standardize a solution of barium hydroxide. He weighs out 0.989 g potassium hydrogen phthalate (KHC8H4O4, treat this as a monoprotic acid). It requires 25.0 mL of barium hydroxide to reach the endpoint.
A. What is the molarity of the barium hydroxide solution?
This barium hydroxide solution is then used to titrate an unknown solution of hydroiodic acid.
B. If 18.0 mL of the barium hydroxide solution is required to neutralize 23.6 mL of hydroiodic acid, what is the molarity of the hydroiodic acid solution?
In: Chemistry
A voltaic cell consists of Cu²⁺/Cu and Cd²⁺/Cd half-cells. Each compartment has a volume of 0.500 L with the following initial concentrations: [Cu²⁺] = 1.250 M; [Cd²⁺] = 0.250 M at 25°C. What is the [Cu²⁺] when the voltage has dropped to 0.719 V? (E⁰ for Cu²⁺/Cu = 0.340 V and E⁰ for Cd²⁺/Cd = -0.400 V.)
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Be sure to answer all parts. Calculate the volume in mL of a solution required to provide the following:
(a) 2.24 g of sodium chloride from a 0.415 M solution ___mL
(b) 5.40 g of ethanol from a 4.20 M solution ___mL
(c) 8.30 g of acetic acid (CH3COOH) from a 0.900 M solution ___mL
In: Chemistry
Based on the calculated values of Kc for each reaction stoichiometry, which reaction is the valid one?
Fe(aq)3+ + SCN(aq)- FeSCN(aq)2+ The average value of Kc: 369.10
Fe(aq)3+ +2 SCN(aq)- Fe(SCN)2(aq)+ The average value of Kc: 988999.02
Briefly explain your conclusion. Compare the percent difference between the average value and the individual measurements. What does this tell you about the two possible stoichiometries? Do these reactions give consistent values of Kcfor different initial reaction conditions?
In: Chemistry
how many grams of H2O can be produced when 45.5g of C3H8 reacts?
In: Chemistry