A beaker with 175 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 8.20 mL of a 0.400 MHCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.

A sample of gas occupies 300 ml at STP. Under what pressure would this sample occupy a volume of 150 ml at a temperature of 546 ̊C?

Calculate the pressure exerted by 60.0 g C2H6 (ethane) in a 30.0-L vessel at 27 ̊C.

When nickel is heated in carbon monoxide, a gaseous product is formed that has a density of 6.57 g/L at 750 torr and 40 ̊C. The compound is analyzed to show 34.30% Ni, 28.1% C and 37.53% O. What is the molecular formula of the compound?

If 2.0 liters of N2 at 2.0 atm and 2.0 liters of H2 at 1.0 atm are put in a 4.0-liter vessel, what is the final pressure, temperature being constant?

Two gases, Ar and He, are contained in vessel. The mole fraction of He is 0.35 with a partial pressure of 1.15 atm. What is the partial pressure of Ar?

Given the reaction below, how many grams of iron are needed to produce 100 liter of hydrogen gas at STP?

3Fe(s) + 4H2O(l) → Fe3O4 (s) +4H2 (g)

What volume of oxygen at 18 ̊C and 750 torr can be obtained from the thermal decomposition of 100-g KClO3?

2KClO3 (s) → 2KCl(s) +3O2 (g)

A student collects 2.63 L of O2 over water at 29 ̊C and 769 torr by thermal decomposition of potassium chlorate. a) How many grams of oxygen are in the sample? b) How many grams of KClO3 decomposed to produce the oxygen?

2KClO3 (s) → 2KCl (s)+ 3O2 (g)

A 25.00 mL sample of 0.280 M NaOH analyte was titrated with 0.750 M HBr at 25 °C. Calculate the initial pH before any titrant was added. Calculate the pH after the 5.00ml titrant was added.

Metallic magnesium can be made by the electrolysis of molten MgCl2.

(a) What mass of Mg is formed by passing a current of 6.79 A through molten MgCl2 for 1.80 days? The unbalanced chemical reaction representing this electrolysis is shown below. MgCl2 Mg + Cl2 g of Mg is formed by this electrolysis.

(b) How many minutes are needed to plate out 11.00 g of Mg from molten MgCl2 using 5.46 A current? minutes are needed.

Consider the following reaction:
HC2H3O2(aq)+H2O(l)?H3O+(aq)+C2H3O?2(aq)
Kc=1.8

The toxic effects of ingesting methanol can be reduced by administering ethanol. The ethanol acts as a competitive inhibitor of methanol by displacing it from LADH. If an individual has ingested 50 mL of methanol, how much 100 proof whiskey (50% ethanol by volume) must be imbibed to reduce the activity (Vo) of his LADH towards methanol to 3% of its original value? The adult human body contains ~40L of aqueous fluids throughout which ingested alcohols are rapidly and uniformly mixed. Assume the concentration of methanol in the body is 18mM and whiskey is 6.5M ethanol. Assume the KM values of LADH for ethanol and methanol to be 10-3 M and 10-2 M, respectively, and that Ki = KM for ethanol.

Calculate the pH for each of the following cases in the titration of 50.0 mL of 0.110 M HClO(aq) with 0.110 M KOH(aq). The ionization constant for HClO (4.0x10^-8) I need answers for each one. Thanks!

(a) before addition of any KOH

(b) after addition of 25.0 mL of KOH

(c) after addition of 35.0 mL of KOH (

d) after addition of 50.0 mL of KOH

(e) after addition of 60.0 mL of KOH

answer is 5.84 g, 250 mL

An aqueous solution containing 5.26 g of lead(II) nitrate is added to an aqueous solution containing 7.33 g of potassium chloride.

Enter the balanced chemical equation for this reaction. Be sure to include all physical states.

balanced chemical equation:

What is the limiting reactant?

lead(II) nitrate

potassium chloride

The percent yield for the reaction is 84.1%84.1%. How many grams of the precipitate are formed?

precipitate formed:

How many grams of the excess reactant remain?

excess reactant remaining:

We have seen from our study of acid/base chemistry that the presence of a weak base such as ammonia (Kb = 1.8 X 10-5) can affect the pH of an aqueous solution. This pH can in turn affect the solubility of a metal hydroxide salt as a result of the common ion effect. The Ksp for gallium hydroxide = 7.28 X 10-36. What is the molar solubility of gallium hydroxide in a 3.00M solution of ammonia?

If Kc = 4.4 x 10^-2 for PCl3(g) + Cl2(g) ⇄ PCl5(g) at 520 K, what is the value of Kp for this reaction at this temperature? Express your answer using two significant figures.

Analysis of Group 1 Cations

1) Explain what you would do to prove that a solution contained mercury(I) ion.

2) You are given a white solid and told that it is either strontium nitrate or lead(II) nitrate. Explain what you would do to determine the identity of the solid.

3) You are told that an acid is either hydrochloric acid or nitric acid. What simple test could you carry out to tell which acid it is?

4) You are given a solution and asked to determine which group I cations are present in it. Addition of hydrochloric acid results in the formation of a precipitate. The precipitate is washed with hot deionized water. When the filtrate from hot water washing is tested with potassium chromate solution, a precipitate forms. When a solution of ammonia is added to the remaining precipitate from the addition of HCL, it completely dissolves. What do you conclude?

5) A yellow solid is either lead(II) chromate or sodium chromate. What would you do to tell which compound the solid is?

6) Givee an example of a group(IV) cation in the qualitative series.

1. Calculate [OH?] for 1.7

Based on the addition of NaOH to water, describe why buffers are important in biological systems?

Consider the titration of 100.0 mL of 0.500 M CH3NH2 by 0.250 M HCl. (Kb for CH3NH2 = 4.4×10-4) Part 1 Calculate the pH after 0.0 mL of HCl added. pH = Part 2 Calculate the pH after 25.0 mL of HCl added. pH = Part 3 Calculate the pH after 80.0 mL of HCl added. pH = Part 4 Calculate the pH at the equivalence point. pH = Part 5 Calculate the pH after 300.0 mL of HCl added. pH = Part 6 At what volume of HCl added, does the pH = 10.64? mL