To get around the problem presented in question 2, the internal standard technique is used. An internal standard is a volatile compound that does not interfere with the GC analysis.

• 10.0 mg of internal standard compound (Std) added to 50.0 mg of the mixture of A, B, and C (problem 2) to give a mixture with a total mass of 60.0 mg.

• The sample is analyzed by GC.

• Relative Peak Areas: Std (1.00), A (0.75), B (3.00). Remember C does not elute.

• Based off of the 10.0 mg of internal standard added to the sample, what are the weight percentages of A and B in the original sample?

Determine the pH of a solution when 22.7 mL of 0.028 M HNO3 is mixed with 19.6 mL of

A) 0.0120 M NaOH.
B) distilled water
C) 0.0080 M HCl
D) 0.144 M KOH

Balance the following equation for reactions occurring in acidic solution: MnO4__ + H2S Mn2+ + S

Two objects of different composition with same mass are painted black and are placed in the sun at the same time. After 10 minutes object B is hotter than object A . Which has the higher specific heat . Explain 2.) Gold has a density of 19.3g / cm cube . If a chain necklace has a mass of 605g and volume of 42.7 cm cube , is the chain pure gold? Show calculations and explain basic concept of density.

1.why is it that ammonia can solvate the electron given by Na? how does it do this.

2. why is it that Na is explosive with water but not in ethanol when in both solvents the product is hydrogen?

3. Why cant ethanol or whatever solvate the electron like ammonia does?

please give a detailed explanation.

What is the ratio of the mass of fresh water produced to the mass of water in the incoming brine?Multi-stage flash distillation is used to desalinate seawater so it is fit for human consumption. A flash distillation tank is composed of small chambers (called \"stages\"), each at a lower pressure than the previous stage. Salt water enters the first chamber, some fresh water flash evaporates, condenses, and is removed from the distillation tank. The remaining salt water moves to the next chamber, some fresh water flash evaporates, condenses, and is removed from the distillation tank. The remaining salt water moves to the next chamber, and the process repeats until very salty water is expelled as waste. Brine that is 35,000 ppm salt is desalinated through a 5-stage flash distillation process. The pressure in the stages is such that 8.5% by mass of the water entering the stage evaporates and leaves as fresh water. If the desalination plant wants to produce 1200.0 gallons of drinking water per day, how many gallons of brine must the plant take in per day? The density of fresh water is 1.000 g/cm3. The density of brine is 1.025 g/cm3.

What mass of waste brine is expelled in one day?

What is the ratio of the mass of fresh water produced to the mass of water in the incoming brine?

The larger this ratio is, the more fresh water is produced for the given incoming water. If additional stages are added, each removing 8.5% of the available incoming water, so that the above ratio gets above 0.5, what are the total number of stages in the multi-stage flash distillation tank? (respond with a whole number)

The energy requirement of this type of desalination plant is 25.5 kW·h/m3 of fresh water. How much energy does the plant require to produce 1200.0 gallons of fresh water?

Consider the equilibrium reaction

CO(g)+H2O(g)⇋CO2(g)+H2(g)

Determine how each change in the left-hand column will stress the system and in which direction the equilibrium reaction will shift in response.

Drag the appropriate labels to their respective targets

Choices for equilibrium shif:

Forward reaction rate temporarily decreases, Reverse reaction rate temporarily decrease, Reverse reaction rate temporarily increases, Forward reaction rate temporarily increases

Choices for system stress:

increase reactant , increase product, decrease product, decrease reactant

Determine Kc for the reaction (justify all your calculations):

½ N2(g) + ½ O2(g) + ½ Br2(g) NOBr(g)

From the following information at T=298 K

2NO(g) O2(g) + N2(g) Kc = 2.1 x 10^30

NO(g) + ½ Br2(g) NOBr(g) Kc = 1.4

What is the molality of a solution that has been prepared by mixing 53.6 g of sodium chloride with 464 g of water?

1) A 150.0 mL solution was prepared by mixing 100.0 mL of 1.00 M HONO (Ka = 4.5 x 10–4 ) with 50.0 mL of 1.00 M NaNO2 . Calculate the pH, [HONO], and [NO2–], once equilibrium has been established.

2). What is the pH, [OH^–], [HF], [F^–], and the percent ionization of a solution prepared as 0.50 M HF ? (HF: K_a = 7.2 x 10^-4)

50 M HF ? (HF: K_a = 7.2 x 10^-4)

3. Consider the reaction:

CO(g) + H₂O(g)    CO₂(g) + H₂(g)

At 800 K the equilibrium constant, K = 16.

If your reaction vessel initially contains 0.050 M CO, 0.050 M H₂O, 0.30 M CO₂ and 0.30 M H₂. What are the equilibrium concentrations of all of the components?

4. What is the pH of a saturated solution of Mn(OH)₂ ( K_sp = 2.0 x 10^–13)?

Mn(OH)₂ (s)   Mn²⁺ (aq) + 2 OH^-(aq)     

5) The weakest strong acids is Nitric acid, with a K_a = 240. The % ionizations of strong acids are rounded off to 100%. Calculate the % ionization of 0.100 M nitric acid without rounding.

6. A. An isotope with atomic number 84 and mass number 212 emits an alpha particle. what are the atomic number and mass number of the resultant atom?

B. An atom of atomic number 48 with a mass number of 113 emits A beta particle. What are the new atomic and mass numbers ?

7. Why does the pH change when CO₂ dissolves in water _?

            
8. The 32 isotope of phosphorus has a half life of 14.3 days. How long will It take for a sample of 100g to decay to 12.5g of phosphorus?

9. The maximum legal limit of arsenic in water is 0.0500ppm (parts per million) for drinking water. Is water with 8.00x10^-6 moles of As per liter suitable for drinking ? Show how you arrive at your answer.

10. How many grams of NaOH are in 2.00 liters of a 0.255molar solution ?

1. in redox reactions, what always happens to oxidizing agents?

2. what is the diinition of a physical property, and how it is used?

3.what is the definition of a chemical reaction, and how is it used?

4. if you are given an unknow liquid that can be either water or hydrocarbon, and the sample is clear, no color, and has no odor. what test would you use for it chemical or physical (and what will you see in the test to prove of support this answer)?

The solubility of CdCO_3(s) in 0.500 M KI_(aq) is 3.0x10^-4 M. Given the K_f for [CdI₄]^2- is 2.8x10⁵ , what is the K_sp for CdCO₃?

2-Give recipe example for electroplating Cu, Au, and Ni. Explain how to prepare the electroplating solution.

1)

Which of the following solutions is a good buffer system?

Which of the following solutions is a good buffer system?