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Stoichiometry

Moles & CO2 and N2 & 3H2 reactions & Matter

A. Considering 3.00 moles of CO2: What is its weight in grams? How many molecules are there. B. Considering the reaction: N2(g) + 3H2(g) → 2NH3(g) Explain why this reaction is spontaneous even though it results in matter being less dispersed

the concentration of Ca^2+

What is the concentration of Ca^2+ (in M) that remains dissolved after addition of .15 mol Ca^2+ and .16 mol C2O4^2- to make a 1.0L aqueous solution? (Ksp= 2.7*10^-9)

Reaction of carbon dioxide with lithium hydroxide

The carbon dioxide that is exhaled by astronauts who are on a space shuttle is scrubbed by pumping the air through canisters of lithium hydroxide, LiOH. The chemical equation for this reaction is: 2LiOH + CO2 --> Li2CO3 + H2O What mass of carbon dioxide can 1.00 kg of lithium hydroxide absorb?

Gas Laws - Volume, Density, and Temperature

1.) The density of liquid nitrogen is 0.808 g/mL at -196 degrees Celsius. What volume of nitrogen gas at STP must be liquefied to make 10.0 L of liquid nitrogen? 2.) Calculate the volume occupied by 2.5 mol of an ideal gas at STP. 3.) A hydrocarbon (compound containing only hydrogen and carbon) was analyzed to be 85.7 mass per

Molarity of Solutions

What is the molarity of nitrate (NO3-) in a solution that was made by adding 54.3 g NaNO3 and 43.5 g of Ca(NO3)2 into 560 mL of water?

Percent by mass composition

While chlorofluorocarbons (CFC) are compounds that seem incredibly useful in industry, they also seem to wreak havoc on the ozone layer. If CFC-211 has a percentage by mass of chlorine of 80.46% and carbon of 10.90%, the rest being fluorine, what is the likely formula for CFC-211?

Mass os a molecule

The mass of one molecule in grams is 2.03 x 10^-22 g, its mass in amu is then?

Percent by mass composition

Bronze is an alloy (a mixture of metals) of copper (Cu) and tin (Sn). A sample of brinze is analysed and found to contain 8.0% tin by mass. Therefore, in this sample, the ratio of copper atoms:tin atoms (Cu/Sn) is

Isotopes

The atmosphere of the planet Argos contains the following atom percentages of the isotopes of argon: 36Ar(atomic mass 35.968 amu), 70.0%, 38Ar (atomic mass 37.963 amu), 20.0% and 40Ar (atomic mass 39.962 amu), 10.0%. The average atomic mass of argon(the atomic mass on the periodic table on Argos) on planet Argos will then be...

Forces in gases and in deep space

1.) How much force is required to inflate a high pressure bicycle tire to 95 pounds per square inch (655 kPa) with a hand pump that has a plunger with an area of 5.0 cm^2? 2.) An object exerts a force of 500. N and sits on an area of 4.5m X 1.5m. Calculate the amount of pressure exerted by the object in torr. 3.) During your t

Chemicals and Temperature

1. How small a change temperature can be detect by touch? How could smaller changes in temperature be detected? 2. What would be expect to observe if KHCO3 reacted with HBr? What test would be performed to identify the product? 3. If a reaction called for a minimum of 0.5 moles of table sugar, C6H12O6, and there was only o

Questions of density and volume

In my lab I determined volumes for two unknown metals by two different methods (displacement in a liquid: V=9ml vs. calculation of all sides: V=8.83 cm3 V=5ml V=4.75 cm3 The volumes are not the same. Which do you believe to be more accurate? Why?

Density Problems

1. The density of an uncooked egg is much less than that of a hard boiled egg. Would it make any difference in this demonstration if the egg was hard boiled? If yes, explain what you would see if the graduated cylinder contained: a) only water b) only salt water c) 1/2 water, 1/2 salt water 2. Would a comparison of a can (

Density of Metals

1. Which is more dense, lead or brass? How it can determine? 2. A sheet of metal has the dimensions 5mm, 25 cm, 55cm and its mass is 14.7kg. Using the densities of metals, can you definitely tell what metal this is? How?

Understanding molar concentrations/volume /equations

1. molar concentration of a liter solution of HCl that has 65 grams of HCl in it? 2. How many grams of NaCl are needed to make a molar solution of 2 liters? 3. How many grams of a glucose are in 1 liter of 10% mass/vloume glucose solns?

Density, Volume

1. Describe two different ways by which you could measure the volume of a small cube. 2. Which is more dense, lead or brass? 3. If the value occupied by a liquid 48mL and the density if 1.2g/mL, what is the mass of the liquid? 4. A recycling plant has chips of hight density poly(ethylene) (HDPE, d=0.92g.mL) used for pla

Dissolving silver bromide in a fixer solution

Solid silver bromide AgBr (s) is removed from the film by dissolving it in an aqueous "fixer" solution containing sodium thiosulfate, Na2S2O3 (aq). This reaction produces NaBr (aq) and Na3Ag(S2O3)2 (aq), which can be rinsed away from the film. A fixer solution is prepared by dissolving 120g Na2S2O3 in enough water to make 4.00 L

Reaction between acrylonitrile, propylene, ammonia, and oxygen

Acrylonitrile (C3H3N (g)) is synthesized by reacting propylene (C3H6 (g)), ammonia (NH3 (g)), and oxygen (O2 (g)), to make C3H3N (g) and H2O (g). Suppose that 1.00 kg C3H6, 1.50 kg NH3, and 2.00 kg O2 are mixed and the reaction proceeds to completion. What mass of each reactant and product is present after the reaction is comple

Writing a balanced chemical equation for combustion of compound X

A compound "X" is composed of 58.77% C, 13.81% H, and 27.42% N, by mass, and has a molar mass close to 100 g/mol. Use this information to write a balanced chemical equation for the combustion of the compound X, assuming that this reaction produces only CO2, H2O, and N2.

Compound Reaction and Observations

2 elements, X and Y, react to form 2 different compunds. 7.00g of X and 4.50g of Y react completely to produce a compound formula XY. 14.0g of X and 3.00g of Y react completely to produce a compound with formula XaYb. Determine values of a and b consistent with these observations.

Chloroform in trihalomethanes

The maximum detected concentration of trihalomethanes (THMs) in a water system was 62.9 microgram/L, which is below the max. permitted level. THMs are compunds with the formula CHXYZ, where X,Y,Z are various combinations of Cl and Br, and are produced by the disinfection of water. An example is chloroform, CHCl3. If chlorofor

Molecule Dose Calculation

Would you please show how to solve the following problem: A anti-inflammatory medication is entirely composed of C, H, and O, and is 75.69 mass % C and 15.51 mass % O. Its molar mass lies between 150 and 300 g/mol. How many molecules of this medication are contained in a dose of 200 mg?

Moles in a solution

Calculate the number of moles of aluminum in a solution containing 10 grams sample. a. 0.742 mole of Al atoms b. 0.371 mole of Al atoms c. 26.98 mole of Al atoms d. 0.121 mole of Al atoms

Molarity of a HCl Solution

Calculate the molarity of a solution prepared by dissolving 3.12 grams of gaseous HCL in enough water to make 26.8 mL solutions. a. 1.6 M HCL b. 0.8 M HCL c. 3.2M HCL d. 5.4 M HCL

Molar Mass of a Compound from Weight

One molecule of a compound weighs 2.03 E-22 g. Its molar mass is: a. 48 gram per mole b. 92.1 gram per mole c. 114 gram per mole d. 122 gram per mole

Volume of Methane

What volume is occupied by 19.6 gram of methane (CH4) at 27 degree Celsius and 1.59 atm? a. 1.71 L b. 18.9 L c. 27.7 L d. 303 L

Grams in a Solution

How many grams of NaCl are contained in 350 ml of a 0.25 M solution of sodium chloride? a. 41.7 gram b. 5.11 gram c. 14.6 gram d. 87.5 gram