General Chemistry Answers

What is the pH of a 0.57 M solution of HCl, a strong acid? Show your work.

Write balanced chemical equations for each of the following reactions that involve acids and bases.

A. aluminum and hydrochloric acid

B. nitric acid and sodium chloride

C. potassium hydroxide and sulfuric acid

Determine which of the following species is the strongest oxidizing agent.

1. NO3-, Ag+, Cr2O72-

2. Ce4+, Br2, Zn

3. Mg2+, Na+, Li+

B. Determine which of the following species is the strongest reducing agent.

4. I-, Fe, Mn2+

5. F-, Zn, Au

A 2.144-g sample of phosgene, a compound used as a chemical welfare agent during World War 1, Contains 0.260g of carbon, 0.347g of oxygen, and 1.537g of chlorine. what is the empirical formula of this substance

What is the concentration of Br^- in a solution prepared by mixing 0.500 L of 0.0450 M KBr and 0.250 L of 0.0250 M CaBr₂?

In the year 2025, NASA was able to find another planet (XXV) which may be able to sustain

life. In order to determine if the planet’s water can sustain an earth organism’s life, Winkler

method was employed to determine dissolved oxygen content. A water sample from planet

XXV was obtained and then treated with the usual reagents for Winkler titration. A 50.0 mL

aliquot of this sample was titrated with the 0.010196M Na2S2O3 standard solution. It

required 4.16 mL of the titrant to reach the starch endpoint.

A. Calculate the amount of dissolved oxygen in the sample in terms of ppm O2. (FW O2 = 32.00)

How much faster does He atom effuse than N₂ molecule at the same temperature? (MM_He = 2g, MM_N₂ = 28g)

Double Indicator Titration

A groundwater sample was analyzed for its total alkalinity (assume that the alkaline constituents come from Na2CO3, NaHCO3 and NaOH, either alone or a permissible combination). For the analysis, a standardized 0.101M HCl solution was used.

Suppose a 30.0-ml sample required 13.2 ml of the titrant to reach phenolphthalein end point. Another 20.0 ml of the same water sample was titrated using methyl orange indicator and used 24.7 ml of the same titrant.

a. Determine the alkaline components of the sample

b. What are the molar concentrations of each component?

c. If the analyst did not boil the distilled water used to standardize the titrant in the problem, what will be the effect on the percentages of each component? Why?

If the temperature is decreased to 5 °C, what is the volume of the sample if the pressure is increased to 96.0 kPa?

An experiment was carried out to determine the mass of Sodium oxide in a solution sample. The sample was dissolved in water to make 200 cm³ of Sodium hydroxide. This solution required 500 cm³of Sulphuric acid to just neutralize it. The concentration of Sulphuric acid was 0.1mol/dm³ (0.1M)