Calculate the total cell number in the original culture

You are given a 500ml culture of Euglena from which a 1 ml sample is taken and put in 49 ml of water. Absorbance was measured on this sample but the reading was off the scale. One ml of this solution is taken and diluted in another 249 ml of water, and this time the OD675nm gave the reading of .27. If the turbidity of .27 corres ...continues

Chemistry problems

1. 0.412 mol of a solid was dissolved in 200 mL of water at 21.2 oC. After the solid had fully dissolved, the final temperature of the solution was 17.9 oC. What is the molar heat of solution of the substance? _______________kJ/mol 2. Use Appendix B and the fact that the heats of formation of OF2 and OCl2 are 24.7 and 80.37 ...continues

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37% by mass of bromine. Determine its empirical formula.

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37% by mass of bromine. Determine its empirical formula. A)BrF B)BrF2 C)Br2F3 D)Br3F E)BrF3 Magnesium reacts with iron(III) chloride to from magnesium chloride( ...continues

Which of the following ions would be more water soluble Hg2+ or methyl mercury (CH3Hg+) ? more lipid soluble? and which one would be more toxic.. and why??

Which of the following ions would be more water soluble Hg2+ or methyl mercury (CH3Hg+) ? more lipid soluble? and which one would be more toxic.. and why??

Calculate the molar heat capacity of mercury in J/(mol degrees C).

7. It takes 585 J of energy to raise the temperature of 125.6 g mercury from 20.0 degrees C to 53.5 degrees C. Calculate the molar heat capacity of mercury in J/(mol degrees C). 8. The specific heat capacity of silver is 0.24 J/(g x degrees C). It takes 3.57 kJ of energy to heat a sample of pure silver from 12.0 degrees C ...continues

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water

See attached file for full problem description. 1. In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: Calculate the value of q (kJ) in this exothermic reaction when 1.70 g of methane is combusted at constant pressure. A. -94.6 B. 0.0306 C. -0.0106 D. ...continues

What is the heat of combustion per gram of butane?

5. The combustion of butane produces heat according to the equation 2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(l) H° = -5,314 kJ What is the heat of combustion per gram of butane? A.–32.5 kJ/g B.–45.7 kJ/g C.–91.5 kJ/g D.–2,656 kJ/g E.–15,440 kJ/g 6. The freezing of water is an example of an exothermi ...continues

The thermochemical standard state of a substance is its most stable state under one atmosphere

16. Which of the following statements is incorrect? A.The thermo chemical standard state of a substance is its most stable state under one atmosphere pressure and at some specific temperature (298 K if not specified) B.A superscript zero, such as H0, indicates a specified temperature of 0C. C.For a pure sub ...continues

Which response includes all of the following substances that have H = 0

See attached file for full problem description. 13. Which response includes all of the following substances that have H = 0, and no other substances? I. HCl(g) II. Na(s) III. HCl(aq) IV. F2(g) A.I and II B. II and IV C.I, II, and IV D.II E.I, II, III, and IV 14. Renewable energy sources are esse ...continues

Lewis structure

3. Draw the lewis structure for: CLNO ONF3 XeF2 OXeF2 HO2CCO2H 4. Which of the following compounds/ions contains a bond angle of 120 degrees? A. CH3Cl B. Ch2Cl2 C. CH3OH D. CO3 2- (ion) E. CO2