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Making a Buffer

How would I make a 10% NaCl 100ml buffer made up from a 5M NaCl stock solution. The NaCl stock is aqueous solution.

Calories from Fat

A person on a 2500-Cal low-fat diet attempts to maintain an intake of no more than 20% of food energy from fat. What percent of the daily fat allowance is represented by a tablespoon of peanut butter (15.0 g and 50.1% fat)? Fat has a food value of about 9.0 Cal/g. A. 14 % B. 27 % C. 2.7 % D. 0.17% E. 5.4 %

Iron Production in a Reaction

How many grams of iron can be produced from 3.50 Kg FeO3 from the following reaction FeO3(s) + 3CO (g)-------->2Fe (s) = 3CO2 (g)

Anaerobic Respiration with Ethanol

If the Density of Ethanol is 0.789 g/ml, Starting with 1.00 Kg of glucose, what is the maximum amount of ethanol in grams and liters that can be obtained by the process of the following reaction C6H12O6 (I)__----> 2 C2H5OH (I) + 2 CO2 (g)

Mole Ratio

When the following equation is balanced, what is the mole ration of H2O to Be3N2? Be3N2 + H2O --> Be(OH)2 + NH3

Benzene and bromine react from bromobenzene

Benzene and bromine react from bromobenzene, as represented by the equation. The densities of benzene and bromobenzene are 0.879 g/ml, respectively. How many mL of bromobenzene can ce prepared from 12.5 mL benzene? C6H6 + Br2 --> C6H5Br + HBr


How many grams of potassium dichromate are required to produce 13 grams acetaldehyde?

Mole, Empirical and Stoichiometry Calculations

Mole Calculations (Determining Avogadro's Number): 1. Calculate the mass of carbon in a diamond that contains 3.33 x 1024 atoms of C. 2. Calculate the mass of chloroform that contains 1,000,000,000,000 molecules of CHCL3. 3. Calculate the number of NaCL formula units in 1.37 g of table salt. 4. Calculate the number of N2 mo


A car gets 9.2 kilometers to a liter of gasoline. Assuming that gasoline is 100% octane (C8H18), which has a density of 0.69 g/cm3, how many liters of air (21% oxygen by volume at STP) will be required to burn the gasoline for a 1250-km trip? Assume complete combustion.

Ultraviolet Radiation in Fluorescence

In the process called fluorescence some substances absorb photons of one kind of radiation (ultraviolet) and give out photons of a different kind, when infrared radiation falls on these materials, visible light is not emitted, why? no further info re fluorescence needed, and which element results if two protons and two neutrons

Balanced chemical equation for biosynthesis

Please help with the following problem. Write the balanced chemical equation for the biosynthesis of ethanol. Label the sucrose and the ethanol in the equation. If you start with one mol sucrose, how many mol ethanol is produced? (Assume complete conversion of sucrose to ethanol.) The density of ethanol is 0.80 g/ml. A

Moles of Sulfur Dioxide

How many moles of Sulfur dioxide are in 1.07 x 10 ^23 molecules of sulfur dioxide? And how many molecules are in 58.1 g of Butane?

Moles in Bromine

How many moles are in 8.50 mL of liquid bromine if the density of bromine is 3.12 g/mL?

Finding the average mass of molecules

What is the average mass in grams of the Cobalt (Co) atom? And how many grams of nitrogen dioxide contain the same number of molecules as 5.00 grams of water?

Molecular Weight by Freezing Point Depression of Solution

A 0.573g sample of a nonvolatile solute is added to 15.6g of napthalene and the mixture warmed until melted. The freezing point of the solution was determined and found equal to 78.1C. The freezing point of naphthalene is 80.2C. How do you find out if the boiling pt and the vapor pressure increases or decreases? How do you

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


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