Homework Help for Chemistry

Structures of some aldehydes and ketones pre lab 14 questions

Define solution with two examples.....

A monatomic ion with a 2+ charge has a mass number equal to 62. If the number of neutrons for the ion is 1.21 times larger than the number of protons, how many moles of electrons are there?

Solid phosphorus, P4(s), reacts with chlorine gas to produce solid phosphorus pentachloride. If 187.82 g of phosphorus reacts with 521.19 g of chlorine, what mass of the excess reactant should remain unreacted?

A rigid container contains 2.50 mol O2, 0.50 mol N2, and 1.00 mol CO2. The total pressure of the system is 200 kPa. The partial pressure exerted by the O2 in the mixture is?

Which element accounts for more than half of the total mass of a human body? Explain. (include somecalculations in your explanation as well)

What is the nature of mercury?

100 kmoles/h of saturated liquid containing 10 mole % pentane, 55 mole % hexane, and 35 mole % heptane was separated using multistage distillation column at 380 mmHg. The top and bottom temperature of the column is 51.3°C and 76°C respectively. It is desired to have 99.5 % recovery of the hexane in the distillate. The mole fraction of the hexane in the distillate should be 0.75. The reflux ratio used was 1.2 the minimum. The θ value for Underwood’s correlation is 1.29. Using shortcut method, calculate the number of tray required and the feed tray location for this distillation. Antoine coefficient for the components was given in Table 1.

Table 1: Antoine equation coefficient

Component

A

B

C

Pentane

6.87632

1075.78

233.205

Hexane

6.87024

1168.72

224.21

Heptane

6.89385

1264.37

216.636

Determine whether the mechanism below is valid for this reaction.
AB+AB⟶AB2+ASlowAB2+C⟶AB+BCFast

Describe the role of fructose 2,6bisphosphate in regulation of glycolsis

Calculate g for the cell reaction nio2+2cl+4h gives cl2+ni+2h2o Ecell=0.320v

The reaction of with is known as the Harcourt-Essen reaction and can be represented as follows:

(1)  

The reaction of with thiosulfate can be used to measure the rate of the preceding reaction.

(2)  

Thus, in the presence of , any produced by reaction(1) will be immediately converted back to by reaction(2). Not until all of the thiosulfate has been consumed will become detectable in solution

The addition of starch assists the visual detection of this 'end-point', as the starch-I complex forms a dark blue solution. Prior to this, the solution is colourless.

This overall process is known as the Iodine Clock Reaction.

Consider only the first reaction. The general rate of reaction(1) can be written as:

 

 

 

where k is the specific rate constant and b, c, and d are the order exponents of the respective reactants. On imposing pseudo first order conditions with respect to , the rate law can be written as:

 

 

 

If a is the initial concentration of in the reaction vessel, and x is the amount by which the concentration of has changed by time t (equal to the concentration of produced), integration yield:

 

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A student makes up the following solutions using 0.0500 M  and 0.0200 M . Each solution has also: 5.00 mL of 1.000 M KI, 10.00mL of 0.750 M and 1.0 mL of 1% starch. The final volume of each solution is 50.00mL. The student begins timing from the moment he pours the solution into the acidic  solution and records the time it takes for the solution to turn blue. 

Calculate a in Solution # AB 5.

____________

 

Calculate x in Solution # AB 5.

____________

 

Using the data for all 8 solutions and linear regression analysis (trendline in Excel), calculate the value of k' to three significant figures.

____________

Please help me answer the question

Part A:  to calculate concentration, use

 

AB1 0.025 M x 2.5 ml = a x 5 ml

 

       0.01 M  x 2.5 ml =  

= 0.005 M

= 0.0025 M

 

     a - x = 0.01 M

- Refer to exercise A to get the ln (a/a-x) for the chosen solution (AB3) composition.

- Complete the spreadsheet using a selection of the Time and Temperature data provided in the table above.

- Plot a graph of  ln (k') vs 1/T ()

- Label the x and y axes appropriately.

- The trend line, with appropriately labeled data points, for this linear relation should be included in the graph. The equation of the line should be displayed and can be used to calculate .

- Resize your Part B graph to suitably fill the 2nd page.

Please help me answer the question

Iodine Clock Experiment

The reaction of with is known as the Harcourt-Essen reaction and can be represented as follows:

(1)  

The reaction of with thiosulfate can be used to measure the rate of the preceding reaction.

(2)  

Thus, in the presence of , any produced by reaction(1) will be immediately converted back to  by reaction(2). Not until all of the thiosulfate has been consumed will become detectable in solution.

The addition of starch assists the visual detection of this 'end-point', as the starch complex forms a dark blue solution. Prior to this, the solution is colourless.

This overall process is known as the Iodine Clock Reaction.

Consider only the first reaction. The general rate of reaction (1) can be written as:

 

 

 

where k is the specific rate constant and b, c, and d are the order exponents of the respective reactants. On imposing pseudo first order conditions with respect to , the rate law can be re-written as:

 

 

 

If a is the initial concentration of in the reaction vessel, and x is the amount by which the concentr:concentration of has changed by time t (equal to the concentration of produced), integration yields:

 

 

Please help me answer the question

Explain what happens to the train cars when the engine car beings moving to the left. In your response, describe the role played by magnetic force.