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Stoichiometry

A hypothetical compound has a formula of X2YZ3.

A hypothetical compound has a formula of X2YZ3. If the atomic masses of X, Y, and Z are 41.2, 57.7 and 63.9 respectively, calculate the % by mass of the compound. If the molecular formula is actually X6Y3Z9, what is the percentage of each element present?

Stoichiometry and Heating Zinc Sulfide

Heating zinc sulfide in the presence of oxygen yields the following: ZnS + O2 (arrow) ZnO + SO2 If 1.72 mol of ZnS is heated in the presence of 3.04 mol of O2, which reactant will be used up? Balance the equation first.

Concentration of Stock Solution

Please explain how I would figure out this problem: From 0.80 L of a glucose stock solution, 4.0L of a 1.8% w/v solution of glucose was prepared. What was the concentration of the stock solution?

The fluoride ion is very toxic.

The fluoride ion is very toxic. Not only does it interfere with glycolysis, but if forms an insoluble precipitate with calcium ions (Ksp = 4.13 x 10-11). Give an explanation as to why CaF2 is insoluble; whereas, other calcium halides are soluble in the order CaI2>CaBr2>CaCl2. How much fluoride (as sodium fluoride) would you h

Stochiometery 4

When 19.8g butane, C4H10 is burned with excess oxygen: 2C4H10g + 13O2g -----> 8CO2g +10H2Og How many grams of oxyen are consumed, how many grams of CO2 & H2O are produced?

Combustion reaction of C4H10O

Consider the following reaction: C4H10O + 6O2-> 4CO2+5H2O deltaH=-2713kj How many grams of water will be produced if the reaction is conducted with 75.6g of C4H10O and 95.5 g of oxygen?

A sample of unknown Y is subjected to elemental analysis

1. A sample of unknown Y is subjected to elemental analysis. The follwoing precentages by weight are found to be: C 40.0% H 6.7% O remainder of % by weight The molar mass is found to be 60.0 g A. Calculate the empirical formula (show work) B. What is the molecular formula of unknown Y. (Inclu

Calculate amount of moles from dissolution

How many total moles of ions are released when each of the following samples dissolves completely in water? (a) 0.24 mol of Na3PO4 mol (b) 51.4 g of NiBr2 3 H2O mol (c) 4.07 1022 formula units of FeCl3 mol

General Chemistry

I need to create 1.0 M solution with 5.21 grams of Na2CO3. I need to create 1.0 M solution with 4.12 grams of NaHCO3 . How much distilled water to is use to create these 1.0 M solutions.

Formation of a gas

A solution containing an unknown amount of methyl alcohol that is dissolved in n-octane is added to an excess of methylmagnesium iodide which is dissolved in the high boiling solvent, n-butyl ether. A gas is evolved from the reaction. The gas is collected and its volume determined to be 1.04 ml (corrected to STP). What is the

Molarities

1. Calculate each of the following quantities. a. grams of solute in 173.4 mL of 0.207 M calcium acetate b. molarity of 576 mL solution containing 21.1 g of potassium iodide c. moles of solute in 145.6 L of 0.726 M sodium cyanide 2. Assuming that the volumes are additive, what is the concentration of KBr in a solution prep

Average Density of the Sun

I need some help figuring this question out: The sun has estimated mass of 2x10^36 and the sphere is of average radius of 6.96x10^5 km, calculate the average density of the sun in units of kg/km^3; kg/m^3; g/cm^3 and lbs./ml (hint: use answer from c to convert).

Natural Phenomena Experiment

My son needs to demonstrate an experiment that can explain natural phenomena or the world of everyday experiences using scientific methods and employ theories to interpret his observations. Any ideas, material lists and steps would be helpful.

Modifying the determination of density of a solid in water

How would you modify the determination of density of a solid if the solid dissolved in water, as sugar does? Would your density measurements be more precise if you used a balance that weighed to more decimal places, but still used the same graduated cylinder for determining the volume?

Mole problem - package of M&M candies contains 50 pieces

A package of M&M candies contains 50 pieces. What fraction of a mole is this? Express in both normal and scientific notation. A package of 50 m&m candies cost 50 cents. How much would a mole of m&m's cost in dollars? Given the annual budget of the US is 2 trillion dollars, how many years would it take the US to pay for a mol

Mole problem - The volume of an M&M candy

The volume of an m&m candy is .65 mL. What volume in cubic meters, would one mole of m&m candies occupy? Next, compare the volume of a mole of m&m's to lake erie, which has a volume of 116 mi^3. How many lakes the size of lake erie would a mole of M&M candies fill.

Solutions, Density, Molecular weight

The alcohol content of hard liquor is normally given in terms of the "proof", which is defined as twice the percentage by volume of ethanol (C2H5OH) present. Calculate the number of grams of alcohol present in 1.00 L of 51 proof gin. The density of ethanol is 0.798 g/mol. (solution in grams, please) Arginine vasopressin is

Determining a molecular formula

Thriophene is a carbon-hydrogen-sulfur compound used in the manufacture of pharmaceuticals. When burned completely in excess oxygen, its combustion products are CO2, H2O, and SO2. Combustion of a 0.535 g sample yields 1.119 g CO2, 0.229 g H2O, and 0.407 g SO2. What is the empirical formula of thiophene? The molar mass of thiophe