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Stoichiometry

Limiting Unbalanced Reactants

Suppose 358 g aluminum sulfide react with 124 g water. Al2S3 + H2O -> Al(OH)3 + H2S unbalanced! What mass of the excess reactant remains?

Volume Reading When Density is Given

The density of diamond is 3.51g/mL and the density of lead is 11.3g/mL. If equal masses of diamond and lead were transferred to equal volumes of water in seperate graduated cylinders, which graduated cylinder would have the highest volume reading? Explain your answer.

Purity and Density of metals

Determination of density has many practical applications. Is a piece of jewelry pure gold or is it an alloy perhaps of gold and silver? Give that the densities of gold and silver at 25 degrees C are 19.3 and 10.5g/mL respectively and that the volume of the alloy is the sum of the volumes of the metals used, calculate the density

Using Stoichiometry to Solve for Moles

Reaction: CO(g) + 2H2(g) -> CH3OH(g) Questions: 1) How many moles of each reactant are needed to produce 3.60 X 10^2g of CH3OH? 2) What are the number of grams of each reactant needed to produce 4.00 moles of CH3OH? 3) How many grams of hydrogen are necessary to react with 2.85 moles of CO?

Density

1) A material will float on the surface of a liquid if the material has a density of less than that of the liquid. Given density of water as 1.0g/mL, will a block having a volume of 1.2*10^4 in^3 and weighing 350 lb float or sink? 2) The density of pure silver is 10.5g/cm^3 at 20 degrees C. If 5.25 grams of pure silver pell

Significant figures and conversions

Please give rules for significant figures and explain as go along. 1) Put in decimal form and in scientific notation with sig. figures. a) 4.060 + 120.23 + 4.1*10^-2 b) (140) / [7.2*10^3 * 16.43 * (16.43 - 14.26)] 2) How many sig. figures? a) 100 b) 1.0*10^2 c) 1.00*10^3 d) 100. e) 0.0048 f) 0.00480 g) 4.8

Solutions

A solution of sodium cyanide (NaCN)is prepared by dissolving 50 grams into 500ml of solution. What is the Molarity,%(w/v), and ppm of the resulting solution.

Successive dilutions of a solution

A serial dilution is used to prepare solutions containing amounts(grams)of chemicals so small that they would be impossible to measure with ordinary balance. If 5.00ml of a .10 Molar salt (NaCl) solution is diluted to 500ml,then diluted to 500ml of another new solution, what is its concentration. If 5.00 ml of this solution is d

The environmental protection agency (EPA) has proposed a new standard for microparticulates in air: a) how many of these particles are in your room? b)How many of these particles are in each 0.52-L breath you take?

The environmental protection agency (EPA) has proposed a new standard for microparticulates in air: For particles up to 2.5 um in diameter, the maximum allowable amount is 50 ug/m3. a) If your 9.2 ft x 13.8 ft x 8.6 ft dorm room just meets the new EPA standard, how many of these particles are in your room? (Assume the particle

Brackett Series

1) Lines in the Brackett series of the hydrogen spectrum are cause by emission of energry accompanying the fall of an electron from outer shells to the fourth shell. The lines can be calculated using the Balmer-Rydberg equation. See Attachement for equation where m = 4, R = 1.097 x 10-2nm-1 , and n is an integer greater th

Density of a Metal Calculated

A graduated cylinder weighs 46.3 g when empty and holds 35.1 ml water (d = 1.00 g/cm3). An unknown metal is submerged into the water and brings the total volume to 58.1 ml and the mass of the cylinder and contents to 332.3 g. What is the density of the metal?

Density

Nickels are composed of 25% nickel and 75% copper by mass, what is its density (d of nickel = 8.902 g/cm3; d of copper = 8.95 g/cm3)?

Particles

The environmental protection agency (EPA) has proposed a new standard for microparticulates in air: For particles up to 2.5 um in diameter, the maximum allowable amount is 50 ug/m3. If your 9.2 ft x 13.8 ft x 8.6 ft dorm room just meets the new EPA standard, how many of these particles are in your room? (Assume the particles are

Concentration of Particles in Air

If a person breathes in 20m3 of air per day and the air contains 263 micrograms of particulates per m3, how many grams of particulates does a person breathe in per day?

Particular Coal Combustion of Sulfur

A particular coal contains 5.45% by weight of sulfur. How many grams of SO2 gas will be produced when 100.0g of the coal is combusted? S(s) + O2(g) SO2(g)

Calculating a Compound's Solubility

Question: Consider a body of water in equilibrium with solid calcium sulfate (CaSO4), for which Ksp = 4E-5 at 25 degrees Celsius. Calculate the solubility of calcium sulfate in water (in grams/liter) assuming that the other reactions are negligible.

Balanced Chemical Equations - Calcium Carbonate

136. What mass of calcium carbonate is required to react with the sulfur that is produced by burning 1000 kg of coal that contains 3.6 % sulfur by mass? Using a chemical equation convert the mass of coal to a mass of sulfur dioxide, then calculate the amount of calcium carbonate needed.

Molecular mass and moles

First, how many moles are present in each of the following masses? 2.58g of SrSO4 and 2.53 x10-3g of Ag2CO3. Second, going in reverse, How many grams are necessary to obtain the given number of moles? 3.20 x 10-4 moles of NaOH and 6.42 moles of AgNO3.

Radon Level

What does a radon level of 3pCi/L in a home mean. Should you be concerned about a radon exposure at this level? Why or why not?

Hydroxide ion concentration using K or Kw not Ksp

At 25 degrees C, 0.212 g of barium hydroxide Ba(OH)2 (2 in lower position) is dissolved completely in sufficent water to make 0.25 litre final solution. What is the hydroxide ion concentration(in mol per litre) in this solution? Give the answer in scientific notation to an appropriate number of significant figures, and sta

Hydroxide ion concentration

At 25 degrees C, 0.212 g of barium hydroxide Ba(OH)2 is dissolved completely in sufficient water to make 0.25 litre final solution. What is the hydroxide ion concentration (in mol per litre) in this solution? Give the answer in scientific notation to an appropriate number of significant figures, and state the assumption you must

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.