Phenolphhalein indicator is used in this experiment because it changes color in the pH range of 8.0 to 9.6.

Show by calculation that phenolphthalein is an acceptable indicator for the titration of KHP with NaOH.

This is true if the pH at the equivalence point falls within this range.

In essence, what you need to do is to calculate the pH of the unprotonated phthalate salt. You may assume that the concentration of the salt is approximately 0.05 M at the equivalance point.

HINT: The salt is derived from the weak diprotic acid, which has Ka1 = 1.2 * 10^-3 and Ka2 = 3.9 * 10^-6

This question is for a laboratory experiment titled "Determination of the Solubility Product Constant of Calcium Hydroxide" where a saturated solution of Ca(OH)₂ in water was titrated with HCl.

Part 1 Data - Saturated Solution of Ca(OH)₂ in Water:

Volume of Ca(OH)₂ aliquot: 25.00mL

Concentration of standard HCl: 0.1342M

Indicator Used: Bromothymol Blue

Average volume of HCl to reach end point: 7.71mL

a. Write a balanced, net ionic equation for the titration reaction. Use this equation to perform the subsequent calculations.

b. Calculate the [OH^-] in the standard Ca(OH)₂ solution (using the NET ionic equation).

c. Determine the experimental solubility of the Ca(OH)₂ (in mol/L).

d. Determine the experimental K_sp of Ca(OH)₂.

Please explain steps/show equations! Thank you.

This question is for a laboratory experiment titled "Determination of the Solubility Product Constant of Calcium Hydroxide" where a saturated solution of Ca(OH)₂ in 0.02523M NaOH was titrated with HCl.

Part 2 Data - Saturated Solution of Ca(OH)₂ in 0.02523M NaOH:

Volume of Ca(OH)₂/NaOH aliquot: 25.00mL

Concentration of standard HCl: 0.1342M

Indicator Used: Bromothymol Blue

Average volume of HCl to reach end point: 10.26mL

a. Calculate the TOTAL [OH^-] in the saturated solution of Ca(OH)₂ in sodium hydroxide for the solution assigned (Ca(OH)₂ in 0.02523M NaOH).

b. Calculate the [OH^-] that comes from the dissolution of Ca(OH)₂. The total [OH^-] (calculated above) is the sum of the [OH^-] from the NaOH and the [OH^-] from Ca(OH)₂.

c. Calculate the solubility of Ca(OH)₂ in the NaOH solution (in mol/L).

d. Calculate the experimental K_sp of Ca(OH)₂ for the saturated solution of Ca(OH)₂ in NaOH.

Please explain steps/show equations! Thank you.

An experiment was conducted to determine the effect of children participating in a given meal preparation on calorie intake for that meal.   Data are recorded below. Save the data to a format that can be read into R. Read the data in for analysis. Use R to calculate the quantities and generate the visual summaries requested below. You will lose points if you are not utilizing R.

(1) Summarize the data by whether children participated in the meal preparation or not. Use an appropriately labelled table to show the results. Also include a graphical presentation that shows the distribution of calories for participants vs. non-participants. Describe the shape of each distribution and comment on the similarity (or lack thereof) between the distributions in each population. (2 points)

(2) Does the mean calorie consumption for those who participated in the meal preparation differ from 425? Formally test at the alpha = 0.05 level using the 5 steps outlined in the module. (6 points)

(3) Calculate a 90% confidence interval for the mean calorie intake for participants in the meal preparation. Interpret the confidence interval. (4 points)

(4) Formally test whether or not participants consumed more calories than non-participants at the alpha = 0.05 level using the 5 steps outlined in the module. (6 points )

(5) Are the assumptions of the test used in (4) met? How do you know? (2 points)

Data Set for Assignment 2

Calorie Intake for participants

Calorie intake for non-participants

A coil has N turns enclosing an area of A . In a physics laboratory experiment, the coil is rotated during the time interval Δt from a position in which the plane of each turn is perpendicular to Earth's magnetic field to one in which the plane of each turn is parallel to the field. The magnitude of Earth's magnetic field at the lab location is B .

Part A

What is the magnitude Φinitial of the magnetic flux through the coil before it is rotated?

Part B

What is the magnitude Φfinal of the magnetic flux through the coil after it is rotated?

A new vaccination is being used in a laboratory experiment to investigate whether it is effective. There are 288 subjects in the study. Is there sufficient evidence to determine if vaccination and disease status are related?

Step 1 of 8: State the null and alternative hypothesis.

Step 2 of 8: Find the expected value for the number of subjects who are vaccinated and are diseased. Round your answer to one decimal place.

Step 3 of 8: Find the expected value for the number of subjects who are vaccinated and are not diseased. Round your answer to one decimal place.

Step 4 of 8: Find the value of the test statistic. Round your answer to three decimal places.

Step 5 of 8: Find the degrees of freedom associated with the test statistic for this problem.

Step 6 of 8: Find the critical value of the test at the 0.025 level of significance. Round your answer to three decimal places.

Step 7 of 8: Make the decision to reject or fail to reject the null hypothesis at the 0.025 level of significance.

Step 8 of 8: State the conclusion of the hypothesis test at the 0.025 level of significance.

an experiment was preformed under identical conditions as yours. The absorbance of the penny solution was recorded as 0.231 absorbance units. A calibration plot of absorbance vs concentration of cu(II) (mM) yielded the following trendily equations y= 11591x +.50

a. What is the concentration of the original penny solution?

b. How many grams of Cu are in this solution?

c. if the percent Cu was determined to be 2.70 percent what was the mass of the penny?

This is for my biochemistry lab, the experiment is dealing with trypsin and BPTI. I need to make a graph: plot the absorbance change per minute versus the BPTI concentration for each cuvette.

here are my cuvettes and amount of BPTI added to each

1- 0uL BPTI added

2- 10 uL BPTI added

3-20 uL BPTI added

4-30 uL BPTI added

5- 40 uL BPTI added

6- 50 uL BPTI added.

Each cuvette has a different amount of water and trypsin added to them, for a total volume of 100 uL in each cuvette.

I was give a sample of BPTI for which I had to find the concentration. Using the absorbance, I calculated that the concentration was 0.035mM. We then had to dilute this 10-fold, so to 0.0035mM.

I am not sure how to find the concentration of BPTI in each cuvette with this information. The molecular weight of BPTI is 6500. I don't know if that is needed.

I feel like this should be really easy, but I am having trouble doing this.

In an experiment involving the breaking strength of a certain type of thread used in personal flotation devices, one batch of thread was subjected to a heat treatment for 60 seconds and another batch was treated for 120 seconds. The breaking strengths (in N) of ten threads in each batch were measured. The results were

60 seconds:     43    52    52    58    49    52    41    52    56    58
120 seconds:   59    55    59    66    62    55    57    66    66    51

Let μXμX represent the population mean for threads treated for 120 seconds and let μYμY represent the population mean for threads treated for 60 seconds. Find a 99% confidence interval for the difference μX−μYμX−μY . Round down the degrees of freedom to the nearest integer and round the answers to three decimal places.

The 99% confidence interval is

An experiment is performed to study the fatigue performance of a high strength alloy. The number of cycles to crack initiation is measured for twenty specimens over a range of applied pseudo-stress amplitude (PSA) levels. Use the data in the table provided to fit the following three regression models with y = Cycles and x = PSA (note the natural log transform of y for all models):

PSA (x) Cycles (y)

80, 97379

80, 340084

80, 246163

80, 239348

100, 34346

100, 23834

100, 70423

100, 51851

120, 9139

120, 9487

120, 8094

120, 17956

140, 5640

140, 3338

140, 6170

140, 5608

160, 1723

160, 3525

160, 2655

160, 1732

i. A simple linear regression model: lny=β0+β1∙x .

ii. A quadratic polynomial model: lny=γ0+γ1∙x+γ2∙x2 .

iii. A simple linear regression model with a logarithm transformation on PSA: lny=δ0+δ1∙ln⁡(x) .

1. For model (i.), what hypothesis being tested by the ANOVA F-test (in terms of the coefficients of the model)? Interpret the conclusion of this test in the context of the engineering problem.
2. For model (ii.), what hypothesis being tested by the ANOVA F-test (in terms of the coefficients of the model)? Interpret the conclusion of this test in the context of the engineering problem.
3. What is the p-value for testing the significance of the quadratic term in model (ii.) (Ho: γ2=0)? Interpret the conclusion of this test in the context of the engineering problem.
4. Briefly discuss the advantages and disadvantages of each of the three models.