J.R. S.

Thermodynamics / Enthalpy

10/25/18

If the heat of combustion for a specific compound is -1080.0 kJ/mol and its molar mass is 26.89 g/mol, how many grams of this compound must you burn to release 263.60 kJ of heat?

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Chemistry

10/25/18

Find the number of moles in 25.0 grams of C6H6 with the correct number of significant figures.

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Chemistry

10/25/18

Complex Ion Formation

Calculate the concentrations of Ag+ and Ag(CN)2- in a solution prepared by mixing 100.0mL of 5.0x10-3M AgNO3 with 100.0mL of 2.00M KCN.Please help, even if it's just the setup or advice! I don't... more

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Chemistry

10/25/18

General Chemistry

Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 5.60 MJ of energy (in the form of heat) if the temperature of the sodium is... more

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Chemistry

10/25/18

General Chemistry

At constant pressure, which of these systems do work on the surroundings? Check all that apply.___ A(s) + B(s) ---> C(g) ___2A(g) + 2B(g) ---> 5C(g)___2A (g) + 2B(g) ---> 3C(g) ___2A(g) +... more

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Chemistry

10/25/18

General Chemistry

The 1995 Nobel Prize in Chemistry was shared by Paul Crutzen, F. Sherwood Rowland, and Mario Molina for their work concerning the formation and decomposition of ozone in the stratosphere. Rowland... more

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Chemistry

10/24/18

Can you help me with this question?

A mixture of CaCl2 and KCl weighing 0.75 g was reacted with aqueous AgNO3. The reaction converted all Cl- ions to 1.75 g of AgCl. What percent by mass of the original mixture was KCl?

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Chemistry

10/23/18

Triethylamine, N(C2H5)3, has a solubility of 68.6gL, a molar mass of 101.19gmol, and a base-ionization constant Kb=6.0×10−4. What is the pH of a saturated solution of triethylamine in water

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Chemistry

10/23/18

Theoretical and Percent Yield

In an Aspirin preparations, 4.40g of aspirin are obtained from 5.00 g each of salicylic acid and acetic anhydride. Calculate ether theoretical and percent yield of aspirin

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Chemistry

10/23/18

theoretical and percent yield

if .50 moles of salicylic acid .30 moles of acetic anhydride yield .25 moles of Asprin, calculate the theoretical and percent yield

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Biology

10/23/18

DNA Extraction From Strawberries

My science fair project is "What Stage of Maturity do Strawberries Extract the Most DNA?" I did my project. I made a homemade extraction liquid out dish soap, isopropyl, and salt. My problem is,... more

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Chemistry

10/23/18

H2AsO−4 is amphiprotic, with a Ka of 1.7×10−7 and a Kb of 1.8×10−12. An aqueous solution of an H2AsO−4 salt is created. Is the solution acidic, basic, or neutral?

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Chemistry Chemistry Measurement Word Problem

10/23/18

balanced combustion reaction for C6H6 Equation: 2C6H6(l)+15O2(g)--> 12CO2+6H2O(l)_6542 KJ

If 5.300 g of C6H6 is burned and the heat produced from the burning is added to 5691 g of water at 21 °C, what is the final temperature of the water?

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Chemistry

10/22/18

Calculate the pH of a 0.25M solution of F− at 25∘C. The Ka of HF is 6.8×10−4.

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Ap Biology

10/22/18

Enzymes and catalysts

Which statement about enzymes is false?A)At low substrate concentration, the presence of an enzyme greatly increases the rate of a reaction, but once the enzyme becomes saturated, the reaction rate... more

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Chemistry

10/22/18

Determining Reaction Rates

Consider the reaction below:H2(g)+Cl2(g) ----> 2HCl(g)Why is gas pressure not a good property to monitor in order to determine the reaction rate?

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Chemistry

10/22/18

Molarity Conversion

If 38.17 mL of 0.1072 M NaOH is required to titrate a 15.00 mL sample of sulfuric acid, what is the molarity of the acid?Equation: H2SO4 + 2 OH^1- = 2 H2O + SO4^2-Show all work.

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Chemistry

10/22/18

if you have 125.0 g of water at 100.0 degrees celsius, how much energy must be added to vaporize all of it

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Chemistry Conversion Molarity

10/22/18

Molarity Conversion

If 38.17 mL of 0.1072 M NaOH is required to titrate a 15.00 mL sample of sulfuric acid, what is the molarity of the acid? Equation: H2SO4 + 2 OH^1- = 2 H2O + SO4^2- Show all work.

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Chemistry

10/22/18