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Stoichiometry

Working with Mole Fraction and Vapor Pressure

A solution of sodium chloride in water has a vapor pressure of 20.3 torr at 25°C. What is the mole fraction of NaCl in this solution.What would be the vapor pressure of this solution at 45°C? The vapor pressure of pure water is 23.8 torr at 25°C and 71.9 torr at 45°C

Osmotic pressure and molar mass

An aqueous solution of 10.00 g of an enzyme has a volume of 1.00 L at 29°C. The solution's osmotic pressure at 29°C is found to be 0.781 torr. Calculate the molar mass of the enzyme.

Mass percent and Molality Problem in Solutions

Assume that the density of water is 1.00 g/mL. % eth by volume = V of eth / (V of eth + V of water) * 100%. A bottle of wine contains 10.5% ethanol by volume. The density of ethanol (C2H5OH) is 0.789 g/cm3. Calculate the concentration of ethanol in wine in terms of mass percent and molality.

Mole Fraction and Conversions

What is the mole fraction of ethanol (C2H5OH) in a solution made by mixing a 20.0g sample of ethanol with 80.0g of water? What is the mole fraction of methanol (CH3OH) in a 92.5m aqueous solution? Please show all work and explain each step... It has been a while since I have taken chem and this is not my best subject.

Reactions and Moles

How many moles of water are made from the reaction of 2.2 moles of oxygen gas with unlimited quantities of hydrogen gas? Given the reaction:2H2 + O2 > 2H2O

Mass of Water through Vaporization

On january 1st of 2003 there were 50 kg of cucumbers in a vegetable store and they were 99% water by mass. On february 1st of 2003 they were 98% water, by mass due to loss of water through vaporization. What was the mass of cucumbers on February 1st of 2003?

Molarity of a solution

What is the molarity of a solution formed from 20.0 grams of NaCl dissolved in 650.0 mL of H2O?

Nickel Chloride and Sodium Phosphate Reaction

1. Nickel(11) chloride reacts with sodium phosphate to produce nickel(11) phosphate and sodium chloride. NiCl2(aq) + Na3PO4(aq) -----> Ni3(PO4)2 (s) + NaCl(aq) a. Balance the equation above b. Using the balanced equation, find out how many moles of nickel(11) chloride are required to produce 0.479 mol of nickel

Osmotic pressure problem

Brackish water with a salt content around .5 percent by mass is found in semiarid regions such as the American Southwest. Assuming that brackish water has the same density as pure water and contains only sodium chloride, estimate the osmotic pressure of brackish water at 298K. A hint is that the the total molarity is the sum

Antiprotons annihilate with protons

Compute the energy released in joules per event and in kilojoules per mole when antiprotons (the antimatter corresponding to protons) annihilate with protons. An antiproton has the same mass as a proton. Equation: 1 H + 1 H > energy

Empirical & Molecular Formula

When phosphorus is burnt in a free supply of air, diphosphorous pentoxide is formed. During later stages of combustion in a limited supply of air, the flame becomes larger greenish and flickering. Another phosphorus oxide is formed which is a white waxy crystalline solid which melts @ 23.8 degrees C and becomes a gas @ 176 degre

Air bags

Air bags are activated when a severe impact causes a steel ball to compress a spring & electrically ignite a detonator cap. This causes sodium azide(NaN3) to decompose explosively: 2NaN3(s) = 2Na(s) + 3N2(g) What mass of NaN3(s) must be reacted to inflate an airbag to 70.0 L. at STP?

Show work-Oswald process - mass and how much oxygen required?

9) Industrially, nitric acid (HNO3) is produced by the Oswald process represented by the following - what mass of NH3 is needed to produce 5 tones of HNO3? How much Oxygen is required? 4NH3 + 5O2 = 4NO = 6H20 2NO + O2 = 2NO2 2NO2 + H2O = HNO3 + HNO2

Chemical equation with 7 parts

(Any number following an asterisk is a subscript.) Using the balanced chemical equation: C*6H*12O*6 + 2H(positive charge)--> C*6H*14O*6 answer the following A. How many grams of C*6H*12O*6 equals one mole? B. How many grams of C*6H*14O*6 equals one mole? C. How many moles of H(positive charge) react with 1 mol of C*6H*12O*

A equation with 9 parts

(any number following an asterisk is a subscript) Using the equation for the combustion of methane: CH*4(L) + O*2(G) --> CO*2(G) + H*2O(G) answer the following: A. Is the equation properly balanced and if not balance it. B. Name the compounds in this reaction. c. How many moles of O*2 react with 1 mol of CH*4? D. How many

Solubility product constant

A saturated solution of silver chloride, AgCl contains 1.92 mg of AgCl per liter of solution. What is the value of the solubility product constant Ksp for silver chloride? I know that soluability for AgCl at 25 degrees celcius ksp = 1.8 x 10 -10, however I am not sure if I would even need to incorporate this into the equatio

This deals with limiting reactants in stoichiometry

If 350.0 mL of 6.00 M H2SO4 reacts with 45.00 grams of Al in the following reaction, what is the limiting reagent, how many moles of excess reagent will there be, and how many liters of H2 will form? The reaction is: H2SO4 + Al produces Al2(SO4)3 + H2 If you could please show the steps, I'd appreciate it.

Stoichiometry problem dealing with limiting reagents

If 275.0 mL of 0.5000 M ZnCl2 reacts with 1.650 x 10 to 23rd power of AlPO4 compounds in the following reaction, what is the limiting reagent, how many moles of excess reagent will there be, and how many grams of each product will form? 3 ZnCl2 + 2 AlPO4 yields Zn3(PO4)2 + 2 AlCl3 I am substitute teaching, and I would lik

Calculating Molarity and Molality

Question: A sodium chloride solution has a molarity of 1.250 mol/L and a density of 1.050 g/ml. Calculate molality, the mole fraction of water, and the percent by mass of sodium chloride.

Solve: Distance, Velocity, Density and Volume

Questions: 1. If the sun which is 93,000,000 miles away away from Earth was to go out, how long would it take for us to know that this had happened? Light travels at a speed of 3 x 10^8 meters/second. 2. What would the density be (in g/cm^3) of a block that is 4 cm by 15 cm by 12 cm, and has a mass of 4.3 kg? 3. An ob

Mass Balance Problem

Please see the attached file for full problem description. --- Q1. Starting with a pulp with a water content of 99%, how much water must be removed to obtain one ton of paper containing 60% water? Solution. Water removed Pulp

Molarity

5. Calculate the sodium ion concentration when 60.0 mL of 6.0 M sodium carbonate is added to 30.0 mL of 1.0 M sodium bicarbonate.

Solubility Product and Solubility

The solubility product of silver chromate, Ag2CrO4, at 25 degrees Celsius is 4.05 x 10^-12 mol^3/L^3. Calculate the solubility of silver chromate in: a) pure water b) 0.0500 M silver nitrate solution c) 0.0500 M potassium chromate solution

Calculating concentration in a solution

A student pipets 20.00mL of 0.030M Na2SO3 soln. into a large beaker. To this same beaker the student adds 30.00 mL of 0.020M KIO3 soln. and 50.00 mL of distilled water. The student mixes it thoroughly with a stir rod. Calculate the concentration of Na2SO3 and KIO3 in the new solution but before the reaction occurs.

Electrochemical cell

It is given that the electrochemical cell is at 298K. At time zero [Zn 2+ ]= 1.0 x 10 ^-3 M and [Ag +] = 0.500 M. Calculate the molarities of zinc and silver ions after a current of 2.00 amperes flow for 20 hours. Please show step by step and the units you are using.

Density

A cylindrical bar of gold that is 1.5 in. high and 0.25 in. in diameter has a mass of 23.1987g, as determined on an analytical balance. An empty graduated cylinder is weighed on a triple beam balance and has a mass of 73.7g. After pouring a small amount of liquid into the graduated cylinder, the mass is 79.16g. When the gold cyl

Chemistry Problems

1. The following reaction occurs: CaCO3 + 2H- -> Ca2+ + CO2 +H2O If a 25gm sample of calcium carbonate is added to a 75.5 ml HCl (density = 1.125gm/cm3, 26% HCl by mass), calculate the molarity of the HCL remaining in solution (if any) after the reaction is complete. Assume no volume change. 2. A sample of coc

Finding limiting reactant, theoretical yield, and actual yield

An electric furnace produces phosphorus by the following reaction: Ca3(PO4)2(s) + C(s)+SiO2(s)= CaSiO3(s)+CO(g)+P(I) An initial reaction mixture contains 1500g calcium phosphate, 250 g carbon and 1000g silicon dioxide. a) What is the limiting reactant? b) What is the theoretical yield of phosphorus? c) After the reaction