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2 years ago

13

Gold has a molar mass of 197 g/mol. (a) how many moles of gold are in a 3.98 g sample of pure gold? (b) how many atoms are in th

e sample?

1 answer:

Natali5045456 [20]2 years ago

6 0

A.)49.4974874 moles or 49.5 moles
B.)2.980808730172671e+25 or 3e+25

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a student used 10 mL water instead of 30 mL for extraction of salt water from mixture. how may this change the percentage of NaC

ch4aika [34]

If a<span> student used 10 mL water instead of 30 mL for extraction of salt water from mixture, the extraction of salt will be lesser than compared to using 30 mL since less solute will dissolve in 10 mL.</span>

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3 years ago

How Could Spectroscopy Be Used to Distinguish Between the Following

skelet666 [1.2K]

Spectroscopy be used to distinguish between the following is the compound B has a peak at 3200 – 3500 cm⁻¹ in its IR spectrum.

<h3>What is spectroscopy?</h3>

Spectroscopy is the study of emission or absorption of light. It is used to study the structure of atoms and molecules.

The three types of spectroscopy are:

atomic absorption spectroscopy (AAS)
atomic emission spectroscopy (AES)
atomic fluorescence spectroscopy (AFS)

Thus, the correct option is B, the compound B has a peak at 3200 – 3500 cm⁻¹ in its IR spectrum.

Learn more about spectroscopy

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2 years ago

How many grams of sodium acetate ( molar mass = 83.06 g/mol ) must be added to 1.00 Liter of a 0.200 M acetic acid solution to m

Pie

<u>Answer:</u> The mass of sodium acetate that must be added is 30.23 grams

<u>Explanation:</u>

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of acetic acid solution = 0.200 M

Volume of solution = 1 L

Putting values in above equation, we get:

$0.200M=\frac{\text{Moles of acetic acid}}{1L}\\\\\text{Moles of acetic acid}=(0.200mol/L\times 1L)=0.200mol$

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[\text{salt}]}{[\text{acid}]})$

$pH=pK_a+\log(\frac{[CH_3COONa]}{[CH_3COOH]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of acetic acid = 4.74

$[CH_3COONa]=?mol$

$[CH_3COOH]=0.200mol$

pH = 5.00

Putting values in above equation, we get:

$5=4.74+\log(\frac{[CH_3COONa]}{0.200})$

$[CH_3COONa]=0.364mol$

To calculate the mass of sodium acetate for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of sodium acetate = 83.06 g/mol

Moles of sodium acetate = 0.364 moles

Putting values in above equation, we get:

$0.364mol=\frac{\text{Mass of sodium acetate}}{83.06g/mol}\\\\\text{Mass of sodium acetate}=(0.364mol\times 83.06g/mol)=30.23g$

Hence, the mass of sodium acetate that must be added is 30.23 grams

7 0

3 years ago

Which phase of matter has a fixed volume but variable shape?

jek_recluse [69]

The answer is "Liquid".

Hope I could help you!
Have a great day ;)

8 0

3 years ago

Read 2 more answers

PLEASE HELP ASAP PLEASE

USPshnik [31]

Answer:

<em>If it served you, give me 5 stars please, thank you!</em>

<em />

<em>m = </em><u><em>25</em></u><em> </em><em> </em><u><em>Kg</em></u>

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3 years ago