CHEMISTRY COLLEGE

Four different methods are described for validating the results of a particular analysis. Indicate for each whether the method primarily checks the accuracy of the analysis or the precision of the analysis.a. Five aliquots of the same sample are injected for gas chromatographic analysis by one person on the same day.
i. Accuracy
ii. Precision
b. A known amount of analyte is added to an aliquot of the sample and analyzed with sample.
i. Accuracy
ii. Precision
c. Aliquots from a blood sample are sent to three separate laboratories for analysis using the same method.
i. Accuracy
ii. Precision
d. Identical standard are analyzed by two different methods.
i. Accuracy
ii. Precision

Answers

Answer 1

Answer:

Answer:

a) Precision

b) Accuracy

c) Accuracy and precision

d) Accuracy

Explanation:

When an experiment is done more than once to determine if the results are statistically ok, two forms of the validations are possible the accuracy and precision. When the values of the various experiments are close to the known value, then they are accurate. When the values are close to each other they are precise. So, sometimes the results are precise but are not accurate, and vice-versa.

a) Here, the person wants to find if the 5 aliquots will have close results, so, he or she is looking for precision.

b) Here the amount of analyte is already known, and the person wants to identify if the value will be the same when analyzed together with another sample, thus he or she is looking for accuracy.

c) Here the three results will be compared with each other (precision) and with the standard value of the method (accuracy).

d) The methods will be tested, and the values will be compared with the standard known value, so the person is looking for accuracy.

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Modify methionine, below to show its zwitterion form. How do I make Methionine into a zwitterion?

Answers

Explanation :

Zwitter ion : An ion or molecule having separate negatively and positively charged groups.

Methionine is an amino acid with sulfur atom in its molecule .The proton from carboxylic group with get attached to amino group present in the methionine and negative charge will be generated on oxygen atom of a carboxylic group which will get in conjugation with an another oxygen atom of the carboxylic group.

The positive charge will generated on the nitrogen atom due attachment of the proton from the carboxylic group.

As shown in the image attached.

Methionine is an amino acid and like some amino acid, it has a zwitterion form. A zwitterion form is a form of molecule showing separate positive and negative charges. The hydrogen from the carboxylic acid group will transfer to the amino group producing a negative charge at the carboxyl group and a positive charge at the amino group.

Identify the combustion reaction. identify the combustion reaction. c(s) + o2(g) → co2(g) 2 h2(g) + o2(g) → 2 h2o(g) c3h8(g) + 5 o2(g) → 3 co2(g) + 4 h2o(g) 2 c3h7oh(l) + 9 o2(g) → 6 co2(g) + 8 h2o(g) all of the reactions are examples of combustion reactions.

Answers

Combustion reaction occurs when organic compound reacts with oxygen to form CO₂, H₂O and energy
C(s) + O₂(g) → CO₂(g) is Synthesis reaction not combustion
2 H₂(g) + O₂(g) → 2 H₂O(g) also Synthesis reaction and not combustion
C₃H₈(g) + 5 O₂ → 3 CO₂(g) + 4 H₂O(g) is considered as Combustion reaction
2 C₃H₇OH(l) + 9 O₂(g) → 6 CO₂(g) + 8 H₂O(g) Combustion reaction

Answer:

All of the reactions are examples of combustion reactions.

Explanation:

Ocean water is the coldest at

Answers

The bottom of the ocean because it does not get sun light

A sample containing only carbon, hydrogen, and silicon is subjected to elemental analysis. After complete combustion, a 0.7020 g sample of the compound yields 1.4 g of CO2, 0.86 g of H2O, and 0.478 g of SiO2. What is the empirical formula of the compound?

Answers

Answer: The empirical formula of compound is $C_4H_(12)Si$ .

Explanation:

Mass of Sample= 0.702 g

Mass of $CO_2$ = 1.4 g

Mass of $H_2O$ = 0.86 g

Mass of $SiO_2$ = 0.478 g

First we have to calculate moles of $CO_2$ , $H_2O$ and $SiO_2$ formed.

1. Moles of $CO_2=(1.4g)/(44g/mol)=0.032mol$

Now , Moles of carbon == Moles of $CO_2$ = 0.032

2. Moles of $H_2O=(0.86g)/(18g/mol)$ =0.048mol

Now , Moles of hydrogen = $2*$ Moles of $H_2O$ = $2* 0.048=0.096mol$

3. Moles of $SiO_2=(0.478g)/(60g/mol)=0.008$ mol

Now , Moles of silicon = Moles of $SiO_2$ = 0.008 moles

Therefore, the ratio of number of moles of C : H : Si is = 0.032 : 0.096 : 0.008

For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C= $(0.032)/(0.008)=4$

For H = $(0.096)/(0.008)=12$

For Si= $(0.008)/(0.008)=1$

Thus, C: H: Si = 4 : 12 : 1

The simplest ratio represent empirical formula.

Hence, the empirical formula of compound is $C_4H_(12)Si$ .

A primary amine contains a five-membered carbon ring. The degree of unsaturation for the five-membered carbon ring is equal to three. In the chemical formula, there are seven carbon atoms. Determine its chemical formula.

Answers

Answer:

C₇H₁₁N

Explanation:

To find the chemical formula, first, let's evaluate the given conditions.

1.Is a primary amine:

This means that the amine is connected to a carbon, like NH₂-R

2.The degree of unsaturation of the five-membered carbon ring is equal to three:

One of the degrees of unsaturation is for the five-membered carbon ring, the other two are for pi-bonds. This means that the five-membered carbon ring has 2 pi-bonds inside.

3.There are seven carbon atoms:

Five of these seven carbons are for the carbon ring and the other two are bonded to the primary amine.

From all of the above, we have that the chemical formula is:

C₅H₅-C₂H₄-NH₂ = C₇H₁₁N

I hope it helps you!

Calculate ΔHrxn for the following reaction: C(s) + H2O(g) --> CO(g) + H2(g) Use the following reactions and given ΔH values: C (s) + O2 (g) → CO2 (g), ΔH = -393.5 kJ 2 CO (g) + O2 (g) → 2 CO2 (g), ΔH= -566.0 kJ 2 H2 (g) + O2 (g) → 2 H2O (g), ΔH= -483.6 kJ

Answers

Explanation:

Below is an attachment containing the solution to the question.

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