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# Stoichiometry

### Creating Molar Solutions

How would you prepare: a.) 250 mL of .1 M KCl b.) 250 mL of .10 M BaCl2

### 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 Comparison of Masses

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?

### Balancing Equations - Oxygen and Iron

How many moles of oxygen are required to form one mole of iron? (See attached file for full problem description)

### A solution containing 292 g of Mg(NO3)2 per liter

A solution containing 292 g of Mg(NO3)2 per liter has a density of 1.108 g/mL. The molality of the solution is a. 2.00 m b. 2.41 m c. 5.50 m d. 6.39 m (See attached file for full problem description)

### 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

### Molality of a mixture of sucrose and water

Suppose we had 1.00 mole of sucrose (it's about 342.3 grams) and proceeded to mix it into some water. It would dissolve and make sugar water. We keep adding water, dissolving and stirring until all the solid was gone. We then made sure that when everything was well-mixed, there was exactly 1.00 liter of solution. What would be t

### Groundwater Leading to Environmental Hazards

If solid water were denser than liquid could it cause water pipes to burst - in essence the water pipes underground would burst due to its density and them not being able to withstand to the cold water flow which could contaminatie the groundwater leading to environmental hazards? Or would the opposite be true?

### Calculation of Total Hardness (TH), Anion-Cation Balance

Calculation of total hardness (TH) and anion-cation balance given total anions.

### Thermochemistry with Heat of Reactions and Standard Enthalpies

1. (Stoichiometry/Heats of Reactions) a. How many kilojoules of heat energy are released when a 63.4-g sample of magnesium metal is completely converted to magnesium oxide according to the equation below? b. How many grams of oxygen gas are used up during an enthalpy change of -292 kJ? 2 Mg(s) + O2(g) -> 2 MgO(s)

### Atomic Weights - The Atomic Mass of N Relative to H

Ammonia is a gas with a characteristic pungent odor. it is sold as a water solution for use in household cleaning. The gas is a compound of nitrogen and hydrogen in the atomic ratio 1:3. A sample of ammonia contains 7.933 g N and 1.712 g H . What is the atomic mass of N relative to H?

### Scientific Notations

Am I correct: 1.0 gram = 1,000,000.0 micrograms or 1 x 10^-6 micrograms 1.0 gram = 1,000.0 milligrams or 1 x 10^-3 mg 3.781 micrograms = 3.781 x 10^-6 is this grams? micrograms? Is it 0.000003781 grams ? Is it .003781 mgs or 3.781 x 10^-3 mg? Does this mean that 3

### Individual molecules in 1 mole of sugar and 1 mole of salt

Which has more individual molecules (formula units): 1 mole of sugar or 1 mole of salt?

### Working with amount of molecules - moles, mass, weight

Which has the greatest mass, 2 moles of sodium chloride or 5 moles of carbon dioxide? Show all work and include units

### Molar Mass and Formula of Compounds

Determine the formula and molar mass for each of these compounds Sodium Chloride Potassium Bicarbonate Calcium Phosphate Sodium Fluoride Ammonium Hydroxide.

### Working with measures - mol, gram, number

How many grams are in 1 mole of table salt (NaCl). How many individual ionic compounds of NaCl are in 1 mole?