Lab 02

Explain your rationale for using the summative assessment (below) from the lesson plan on mixing substances in a 5th-grade classroom based on the below standard and learning objective, including how it aligns with the learning objective.  Summative Assessment  Summative: Components of the Lab Report Purpose: The student should clearly state the purpose of the experiment, which is to determine whether the mixing of two or more substances results in new substances. Procedure: The student should describe the steps they took to conduct the experiment. This includes the substances they chose to mix and the safety equipment they used. Observations: The student should record any observable changes that occurred when the substances were mixed. This could include a color change, the formation of a precipitate, or a change in temperature. Conclusion: The student should state whether a new substance was formed based on their observations. They should also reflect on their accuracy in…

A sample was placed on a chromatography column. Methylene chloride was used as the eluting solvent. No separation of the components in the sample was observed. What must have been happening during this experiment? How would you change the experiment to overcome this problem?

How many of the following should be included in a good hypothesis? (1) A prediction of the results of the experiment (ii) A step-by-step walkthrough of how to do the experiment with specific references to amounts of reactants, glassware used, and other experimental details (iii) A summation of the data collected after doing the experiment, with comments on accuracy and precision if possible. (iv) A detailed list of chemicals that will be used (vi) A brief scientific explanation of the predicted results. Said another way, the hypothesis should include a scientific explanation of why the predicted results are expected. (v) Waste disposal procedures 0 1 O 2 O 3 0 4 0 5

What are replicates in Analytical Chemistry? O The component of a sample that repeats over different assays. Similar assays done to different samples A sample that contains exactly the same amount of analytes than the original sample similar samples that are analyzed at the same time and in the same way

The following volumes of 0.000300 M SCN are diluted to 15.00 mL. Determine the concentration of SCN in each sample after dilution. These values will be used during the experiment. To enter exponential values, use the format 1.0e-5. Sample 0.000300 M SCN (mL) [SCN'] (M) 1 1.50 3.50 7.00 4 10.00 3.

42.How many of the following should be included in a good hypothesis? (i) A prediction of the results of the experiment (ii) A step-by-step walkthrough of how to do the experiment with specific references to amounts of reactants, glassware used, and other experimental details (iii) A summation of the data collected after doing the experiment, with comments on accuracy and precision if possible. (iv) A detailed list of chemicals that will be used (v) Waste disposal procedures (vi) A brief scientific explanation of the predicted results. Said another way, the hypothesis should include a scientific explanation of why the predicted results are expected.   A. 1   B. 2   C. 3   D. 4   E. 5

There are 48 pairs of students in the following table. Each pair has quantitatively determined the mass of caffeine in a 355 mL can of the popular energy drink marketed as “GRIME” using Liquid Chromatography-Mass Spectrometry (LC-MS). The class results are presented below. Summarise and report these results including an indication of measurement uncertainty. * Mass of Caffeine (mg) Mass of Caffeine (mg) (Table continued) 208.28 207.54 207.12 206.70 208.54 208.00 208.23 208.49 207.99 206.85 208.74 207.73 206.93 207.27 206.77 208.88 207.55 206.97 208.42 208.65 208.68 208.81 207.59 208.41 207.89 208.42 208.11 206.75 206.49 208.13 207.97 206.79 200.79 208.08 207.69 207.79 207.92 207.85 206.57 208.12 206.89 208.38 207.27 208.15 207.89 206.62 207.71 207.83

Conservation of mass was discussed in the background. Describe how conservation of mass (actual, not theoretical) could be checked in the experiment performed.

Give two examples of the Scale Factor Error (one of the types of systematic error). Please do not give what is already given in the example. I need it ASAP Thank you

What are the similarities in random error and systematic error? In analytical method and graphical method?

7. 22 This question is about several salts. (a) A hydrated salt, compound A, is analysed and has the following percentage composition by mass: Cr, 19.51%; CI, 39.96%; H, 4.51%; O, 36.02%. Calculate the formula of compound A, showing clearly the water of crystallisation. Show your working. formula of compound A = (b) A student carries out an experiment to determine the amount of water of crystallisation in the formula of another hydrated salt. The student intends to remove the water by heating the hydrated salt. A diagram of the apparatus used by the student is shown below. crucible pipeclay triangie The student adds the hydrated salt to the crucible and weighs the crucible and contents. The student heats the crucible and contents and allows them to cool. The student weighs the crucible and residue. The student's results are shown below. 16,84 Mass of crucible + hydrated salt/g 16.26 Mass of crucible + residue after heating/g

You are trying to determine average experimental value with relative uncertainty for the volume of water measured in a 100 mL volumetric pipet with 0.08 mL precision. You follow the procedure below: 1. Weigh a 200 ml flask with a stopper on the analytical balance. Add 100 mL of distilled water measured carefully with a volumetric pipet and re- weight the flask and stopper with the water. 2. Empty the water from the flask and repeat the above procedure two more times for a total of three measurements for the pipet. You collect the following data in your lab notebook: In Lab Data Analytic Balance: Max weight 400 0.0007 g Volumetric Pipet: 100±0.08 ml Density water 1.000 g/ml Trial 1 2 3 Measured Volume (ml) 100.00 100.00 100.00 What is the average percent error in the volumes measured by the pipet? Notes: Canvas will not accept units, so please just input your value-with the correct sig fig Type your answer... Measured Mass (g) 98.1411 98.2413 98.9825

FINAL Experiment 1- January 2021_-789644623 - Saved Layout Review View Table A friend of yours went panning for gold last weekend and found a nugget that appears to be gold. With your newfound scientific prowess, you set out to determine if it is really gold. Your tests show that the nugget has a mass of 7.6 g. Immersing the nugget in water raised the volume from 7.22 mL to 8.06 mL. The density of gold is 19.32 g/cm3. What will you tell your friend? acer

Normality of a solution was determined by five different titrations. The results were 9.5 mL, 8.5 mL, 9.1 mL, 9.3 mL, and 9.1 mL. Calculate the mean, median and standard deviation of this data

Errors of different varieties may arise throughout the course of an experiment. Below, match the different types of errors with their corresponding definitions. Group of answer choices Errors that have an equal chance to be positive or negative. These errors will arise because it is impossible to make any measurement completely exact. Errors that will have a consistent directional bias every time the experiment is carried out. These errors tend to always be positive or negative, meaning over or underestimating, respectively, the true value of the measurement due to experimental limitations. An error that is within the direct control and/or caused by a mistake from the chemist. Options Random error Systematic error Human mistake

Identify two (2) possible errors during weighing a sample.

Describe the essential features of a well-designed experiment.

Give two examples of Gross Errors. Please do not give what is already given in the example. Thank you

Based on this. What was the percentage error in the percentage of water in the sample, compared to pure MgSO4•7H2O?

After creating her standard curve for absorption versus the concentration (M) of FD&C Red 40 and processing her data, Sally found that her drinking strength Kool-Aid sample had an FD&C Red 40 concentration of 1.086 x 10–5 M. If 0.133 grams of Kool-Aid powder was used to prepare an 8-fl oz cup of her assigned flavor, what is the percent by mass of FD&C Red 40 in her Kool-aid powder?

What is the difference between precision and accuracy in analytical chemistry? Give an example from everyday life

To analyze the residual toxins and sugar content of a sample of a fruit, propose and discuss the chromatographic method.

Sucrose solution for experiment 1: (Question a-c)Prepare a solution of sucrose by accurately weighing 9.0 – 9.25 g of sucrose into a 100mLbeaker / conical flask. Record the mass of the sample. Add 25 mL distilled water. Mix until allcrystals dissolve.NaCl solution for experiment 2: (Question d-f)Prepare a solution of NaCl by accurately weighing approximately 1.5 g of NaCl into a 100 mLbeaker / conical flask. Record the mass of the sample. Add 25 mL distilled water. Mix until allcrystals dissolve.MgCl2٠6H2O solution for experiment 2: (Question d-f)Prepare a solution of magnesium chloride by accurately weighing approximately 3.6 g ofMgCl2٠6H20 into a 100 mL beaker / conical flask. Record the mass of the sample. Add 25 mLdistilled water. Mix until all the crystals dissolve

How will each of the following experimental errors influence the results of your calculated densities you reported? State whether the error will tend to make your density results too large, too small or unchanged. Explain why this would occur by identifying which measurements would be affected (high or low) and how this would affect the calculated density. Use the followingIn method 2, the metal cylinder you used had a number of air bubbles on its when immersed in the water

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