After a certain H atom emits a 3740 nm photon, the energy of its electron is -8.716 x 10-20 J. What was the electron's energy before photon emission, and what level did it occupy?

If we have a mixture of sodium carbonate and sodium hydroxide, what procedure allows us to tell that they are both present?

Based on your results which measurement do you think will be more accurate and which do you think is more precise. Explain why.

Hydrogen fuel has been used in fuel cells or internal combustion engines. Determine the heat of combustion, energy capacity, and carbon footprint of the fuel.

ΔHf H2O(l) = -285.8 kJ/mol

A 50.0-mL volume of 0.15 M HBr is titrated with 0.25 M KOH. Calculate the pH after the addition of 13.0 mL of KOH. Express your answer numerically.

A 75.0-mL volume of 0.200 M NH3 (Kb=1.8×10−5) is titrated with 0.500 M HNO3. Calculate the pH after the addition of 15.0 mL of HNO3.

Express your answer numerically.

A 52.0-mL volume of 0.35 M CH3COOH (Ka=1.8×10−5) is titrated with 0.40 M NaOH. Calculate the pH after the addition of 33.0 mL of NaOH.

Express your answer numerically

Balance this reaction, show all steps? (Answer given)

AsO3 (-3) + MnO4 (-1) ----> AsO4 (-3) + Mn (2+)

Answer:

5AsO3 + 2MnO4 + 6H+ ---> 5AsO4 + 2Mn + 3H2O

Please show the steps in between like the half reactions and balancing them. Thanks

Write balanced net ionic equations for the following reactions in basic solution.

A. S2O32−(aq)+I2(aq)→S4O62−(aq)+I−(aq)

Express your answer as a chemical equation. Identify all of the phases in your answer.

Part B Mn2+(aq)+H2O2(aq)→MnO2(s)+H2O(l)

Part C Zn(s)+NO3−(aq)→NH3(aq)+Zn(OH)42−(aq)

Part D Bi(OH)3(s)+Sn(OH)3−(aq)→Bi(s)+Sn(OH)62−(aq)

Given the equation: Al₂C₆ + H₂O --> Al(OH)_{3 +} CH₄(g)

a) If 34.5 grams of Al₂C₆ is mixed with 72.0 grams of water, what mass of Al₂C₆ is formed?

b) If 34.5 grams of Al₂C₆ is mixed with 72.0 grams of water, what mass of Al(OH)₃ is formed?

c) If 34.5 grams of Al₂C₆ is mixed with 72.0 grams of water, what volume of CH₄ is formed at STP?

The reaction of glucose, C6H12O6, to carbon dioxide and water is a common reaction in the body. C6H12O6 (s) + _6__ O2 (g) → __6__ CO2 (g) + __6__ H2O (g)

If you eat 15.0 g of glucose from some candy you eat, how many grams of carbon dioxide will you produce?

If the density of water at body temperature (37 ⁰C) is 0.9933 g/mL, how many mL of water is produced from this reaction?

Identify the molecular geometry for each of the following triatomic molecules using the VSEPR model. Then, determine which molecules would be expected to have at least one normal mode that is infrared active. Explain your reasoning

a. NO2

b. PCl2 +

c. BrF2 -

d. N3 -

What is the percent yield of the solid product when 12.01 g of iron(III) nitrate reacts in solution with excess sodium phosphate and 5.008 g of the precipitate is experimentally obtained?

Fe(NO₃)₃(aq) + Na₃PO₄(aq) --> FePO₄(s) + NaNO₃(aq) [unbalanced]

A 30.00-mL solution of HBr was treated with 5 mL of freshly boiled and cooled 8 M HNO3, and then with 50.00 mL of 0.3650 M AgNO3 with virgorous stirring. Then 1 mL of saturated ferric alum was added and the solution was titrated with .2870 M KSCN. When 3.60 mL had been added, the solution turned red. What was the concentration of HBr in the origninal solution? How many millimgrams of Br- were in the original solution?

Mg(OH)2 is a sparingly soluble salt with a solubility product, Ksp, of 5.61×10−11. It is used to control the pH and provide nutrients in the biological (microbial) treatment of municipal wastewater streams. What is the ratio of solubility of Mg(OH)2 dissolved in pure H2O to Mg(OH)2dissolved in a 0.160 M NaOH solution?

Express your answer numerically as the ratio of molar solubility in H2O to the molar solubility in NaOH.

How many milliliters of a 1% w/v epinephrine injection must be used to prepare 20 mL of an injection containing 1:200,000 w/v epinephrine?

Chemical cold packs used for sports injuries are made with solid ammonium nitrate (NH4NO3) and a plastic bag of water. When the bag of water is broken the ammonium nitrate dissolves.

NH4NO3(s) --> NH4+ (aq) + NO3- (aq)

As the solution forms, the water and bag get colder.

Which of the following is true for this process. ( Assume the reaction above is our system) Chose all that apply

Select one or more:

a. The process is endothermic.

b. Δ H for the reaction is positive

c. q for the water is positive.

d. The process is exothermic.

e. The solid ammonium nitrate has more enthalpy (H) than the ammonium and nitrate ions.

f. q for the water is negative.

g. The solid ammonium nitrate has less enthalpy (H) than the ammonium and nitrate ions.

h. q for the reaction is negative.

i. q for the reaction is positive.