Explain the spectral differences between the spinach and the Cordyline fruticose leaves.

What determines the leaf color in plants? Provide a structure and of the molecule and explain why green is the predominant color.

Why do deciduous trees change color in the fall (biochemical explanation). Provide a molecule responsible for yellow and one for red color. Why are these molecules necessary in addition to the chlorophyll?

Here we have a Radioactive Thermoelectric Generator (RTG) that is powered by Plutonium 238 (²³⁸Pu). The RTG produces 1400 Watts. ²³⁸Pu decays by alpha-particle emission. The alpha-particle has 5.593 MeV of kinetic energy. The half life (t_1/2) of ²³⁸Pu is 87.7 years.

a) Write the nuclear reaction for ²³⁸Pu decay

b) Assume all of the kinetic energy is converted to heat. How much ²³⁸Pu (in grams) must be present to produce 1400 Watts of power?

1. A student prepares a 250.0 mL solution using 41.7 grams of potassium nitrite. They then take 29.9 mL of this solution and dilute it to a final volume of 250.0 mL. How many grams of potassium nitrite are in a 36.2 mL sample of this final diluted solution?

2.

Part A

A beaker with 195 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 4.50 mL of a 0.430 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.

Write the total differential for H as a function of T & P and derive the appropriate working equation.

find the ph of each mixture of acids

0.020m HNO3 and 0.225 Mbr

0.095m in acetic acid and 0.075.m in H2SO4
0.0500 M in HCL04 and 0.02 M HBR

Calcium nitrate and ammonium flouride react to form calcium flouride, dinitrogen monoxide, and water vapor. What mass of each substance is present after 21.83g of calcium nitrate and 22.75g of ammonium flouride react completely?

when 75.5g of calcium and 43.1g of nitrogen gas undergo a reaction that has a 88% yield, what mass of calcium nitride forms?

when 73.8g of calcium and 41.8g of nitrogen gas undergo a reaction that has a 92.4% yield, what mass of calcium nitride forms?

a sample of 0.767 mol of a metal m reacts completely with excess flourine to form 59.9g of MF2. what element is represented by the symbol M?

when 29.8g of methane and 47.6 g of chlorine gas undergo a reaction that has a 74.5% yield, what mass of chlormethane (CH3cl) forms?

Can you have TSS without turbidity? Can you have turbidity without TSS? Explain why based on the physics of the measurement.

1a )When 50.0 mL of 0.500 M HCl at 25.0°C is added to 50.0 mL of 0.500 M NaOH at 25.0°C in a coffee cup calorimeter, the temperature of the mixture rises to 28.2°C. What is the enthalpy of reaction per mole of acid? Assume the mixture has a specific heat capacity of 4.18 J/(g ? K) and that the densities of the reactant solutions are both 1.00 g/mL.

1b) Consider the following reaction: 2 PbS (s) + 3 O2 (g) ? 2 PbO (s) + 2 SO2 (g) ?H = -827.4 kJ How many grams of PbS have reacted if 975 kJ of heat is produced? 1c) Consider the following reaction carried out under constant pressure 3MgO(s) + 2NH3(g) ? 3H2O(l) + Mg3N2(aq) ? Hrxn = 5.78×102 kJ Calculate the heat associated with the complete reaction of 46.0 g of MgO with 17.1 g of NH3.

1.  Discuss the process of water boiling from the molecular point of view. Your explanation should include the effect of atmospheric pressure and the effect of adding a non-volatile solute to the water.

2. Compare and contrast Boyle’s Law and Charles’ Law. Make sure to define and explain both laws prior to discussing their similarities and differences.

Chemical Pairs: sodium chloride versus sodium chlorite barium sulfate versus barium sulfide sodium nitrate versus sodium nitrite sodium hypochlorite versus sodium perchlorate Questions: What are some of the common uses for each of the chemicals in your pair? What are some of the safety concerns for each of these chemicals? (It might help to look up the SDS for each chemical) How are the properties and safety concerns of these two chemicals different? Are they similar? What do you think could happen if you used the opposite chemical in one of the common uses you researched above? What are some of the consequences that could occur? Be sure to include an example for both chemicals you looked up.Chemical Pairs: sodium chloride versus sodium chlorite barium sulfate versus barium sulfide sodium nitrate versus sodium nitrite sodium hypochlorite versus sodium perchlorate Questions: What are some of the common uses for each of the chemicals in your pair? What are some of the safety concerns for each of these chemicals? (It might help to look up the SDS for each chemical) How are the properties and safety concerns of these two chemicals different? Are they similar? What do you think could happen if you used the opposite chemical in one of the common uses you researched above? What are some of the consequences that could occur? Be sure to include an example for both chemicals you looked up.

A 2.20 g sample of the Ethane C2H6 gas was mixed with excess oxygen gas and a combustion reaction occurred to obtain water in liquid aggregate and carbon dioxide state. The combustion reaction occurred at a constant calorimeter under standard conditions.
After the reaction was completed, the temperature in the calorimeter rose by 1.3K. The heat capacity of the calorimeter is 88.8 kJ / K.

1. Write a balanced response to the burning process that took place.
2. Consider the change in standard enthalpy, ∆H for a 1 molar reaction of ethane. Show calculations.
3. Explain how you would calculate ∆H_f [C₂H₆(g)] given you values ​​of:
∆H_f [CO₂(g)] and ∆H_f [H₂O(l)]
Numerical calculations are not required.
4. Determine what the missing data is to calculate the change in the fire enthalpy,
∆H_c of ethane at 100 C?
5. Is a difference between ∆H^o and ∆U^o expected for the reaction formulated in section a? Explain

A-- 1.25 cubic inch (in3) sample of glycerol has a mass of 25.2 grams. What is the mass of a 57-mL sample of glycerol?

b---The pressure of the earth's atmosphere at sea level is 14.7 lb/in2 (pounds per square inch). What is the pressure when expressed in g/m2 (grams per square meter)? (2.54 cm = 1 in., 2.205 lb = 1 kg)

c---Solid calcium oxide is reacted with solid carbon to form calcium carbide (CaC₂) and carbon dioxide.

Write a balanced chemical equation that describes this reaction. (3 points)

If the reaction is carried out using 100.00 grams of calcium oxide and 100.00 g of carbon, how many moles of each reactant are used? (2 points)

d---Ammonium sulfate is primarily used as a fertilizer for alkaline solids. In the soil the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth.

What is the chemical formula of ammonium sulfate? (1 point)

What is the mass percentage of nitrogen in ammonium sulfate? (2 points)

How many moles of ions are released when 13.2 g of ammonium sulfate is dissolved in water? (2 points)

Many radioactive isotopes are used in medicine for imaging and treatment purposes. The specific isotopes used depends on the particular organ or body system being studied (for example, Xe-133 is used to image lung function and blood flow.) For thyroid imaging, isotopes of iodine are used, commonly I-123 and I-131, which have half-lives of 13.2 hours and 8.0 days, respectively.

Why is iodine used for thyroid imaging (as opposed to any other element)?

I-129 is an extremely rare isotope of iodine with a half-life of 15.7 million years. Assuming it was much more abundant in nature, would I-129 be a good substitute for I-123 or I-131 in thyroid imaging? Why or why not?

Although both I-123 and I-131 can be used in imaging of the thyroid, only I-131 is used in treating thyroid cancer. What difference in radioactivity between I-123 and I-131 accounts for this preference?

Sometimes non-radioactive isotopes of iodine can be preferred depending on the intended medical use. For example, many people preparing for a nuclear disaster stockpile KI tablets (non-radioactive). Why would someone consume KI during a radioactive disaster? Would you consider purchasing KI tablets as a precaution? Why or why not?

2.15 mol of an ideal gas with CV,m=3R/2 undergoes the transformations described in the following list from an initial state described by T=350.K and P=5.00bar.

1) The gas undergoes a reversible adiabatic expansion until the final pressure is one-fourth its initial value.

2) The gas undergoes an adiabatic expansion against a constant external pressure of 1.25 bar until the final pressure is one-fourth its initial value.

3)The gas undergoes an expansion against a constant external pressure of zero bar until the final pressure is equal to one-fourth of its initial value.

a) Calculate q for each process. (q1,q2,q3)

b) Calculate w for each process. (w1,w2,w3)

c) Calculate ΔU for each process. (ΔU1, ΔU2, ΔU3)

d) Calculate ΔH for each process. (ΔH1, ΔH2, ΔH3)

e) Calculate ΔS for each process. (ΔS1, ΔS2, ΔS3)