CHEMISTRY COLLEGE

Atomic weight of gold is 197.2 ami
Calculate no of gram atoms in 7.5g of gold

Answers

Answer 1
Answer: the atomic weight is numerically equivalent to the molar mass.
therefore molar mass of gold is - 197.2 g/mol
avagadros number states that 1 mol of any substance is made of 6.022 x 10²³ units. These units could be atoms making up elements or molecules making up compounds. 
1 mol of gold is made of 6.022 x 10²³  atoms of gold
since 1 mol weighs 197.2 g 
therefore if 197.2 g of gold contains - 6.022 x 10²³  atoms of gold
then 7.5 g contains - 6.022 x 10²³  x 7.5/ 197.2 = 2.29 x 10²² atoms of gold 
answer is 2.29 x 10²² atoms of gold

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Which are correct ???

Answers

Answer:

last one

Explanation:

endothermic reactions release energy

QUICK WILL MARK BRAINLIEST!!Match each of the unknown ions to its appropriate description.

A− A) A nonmetal that gained one electron
B+ B) A metal that lost one electron
C2− C) A metal that lost two electrons
D2+ D) A nonmetal that gained two electrons

Answers

Answer:

c2-c

Explanation:

A mental that lost two electrons just joking I don't k ow but I think it ain't the first o e because of comment sense to the 5th power

Answer:

A and B

Explanation:

metal form ion by lossing elecron

non metal form ion by gaining electron

How many amino acids are there and what three general categories do they fall into (i do not mean chemical categories in this question)? please include a one-sentence description of these three categories (3)?

Answers

Technically, there are an infinite number of possible amino acids, though we've found only 20 common ones that many organisms use and at least half a dozen obscure ones that specific organisms use. We focus only on the 20 common ones unless we're in a college level biochemistry course.

The three categories are nonpolar ones, polar ones, and charged ones. The nonpolar ones have non-polar side chains (no oxygens or nitrogens), the polar ones have polar side chains (most contain an OH group but no COOH group), the charged ones are either acidic or basic (has COOH group or a basic nitrogen).

What is the mass of silver chlorate (191.32 g/mol) that decomposes to release 0.466L of oxygen gas at STP? AgC1036) _AgCl). _026) A) 1.33g B) 597 E) 7.968 C) 3.988 D) 2658

Answers

Answer : The mass of silver chlorate will be 2.654 grams.

Explanation :

The balanced chemical reaction is,

2AgClO_3\rightarrow 2AgCl+3O_2

First we have to calculate the moles of oxygen gas at STP.

As, 22.4 L volume of oxygen gas present in 1 mole of oxygen gas

So, 0.466 L volume of oxygen gas present in (0.466)/(22.4)=0.0208 mole of oxygen gas

Now we have to calculate the moles of silver chlorate.

From the balanced chemical reaction, we conclude that

As, 3 moles of oxygen produced from 2 moles of silver chlorate

So, 0.0208 moles of oxygen produced from (2)/(3)* 0.0208=0.01387 moles of silver chlorate

Now we have to calculate the mass of silver chlorate.

\text{Mass of }AgClO_3=\text{Moles of }AgClO_3* \text{Molar mass of }AgClO_3

Molar mass of silver chlorate = 191.32 g/mole

\text{Mass of }AgClO_3=0.01387mole* 191.32g/mole=2.654g

Therefore, the mass of silver chlorate will be 2.654 grams.

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.

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:

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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