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1 year ago

While finding the number of molecules of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be

Chemistry

1 answer:

zvonat [6]1 year ago

8 0

Answer

Avogadro's number: One mole of any substance contains 6.022×10²³ molecules

Explanation

While finding the number of moles of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be Avodagro's number, which is

One mole of any substance contains 6.022×10²³ molecules.

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Phosphorus-32 is radioactive and has a half life of 14.3 days. What percentage of a sample would be left after 12.6 days

nadya68 [22]

Answer:

There is 54.29 % sample left after 12.6 days

Explanation:

Step 1: Data given

Half life time = 14.3 days

Time left = 12.6 days

Suppose the original amount is 100.00 grams

Step 2: Calculate the percentage left

X = 100 / 2^n

⇒ with X = The amount of sample after 12.6 days

⇒ with n = (time passed / half-life time) = (12.6/14.3)

X = 100 / 2^(12.6/14.3)

X = 54.29

There is 54.29 % sample left after 12.6 days

8 0

3 years ago

I begin the reaction with 0.45 g of beryllium. If my actual yield of beryllium chloride (mm = 79.91 g/mol) was 3.5 grams, what w

trasher [3.6K]

The percentage of yield was 777.78%

<u>Explanation:</u>

We have the equation,

Be [s] + 2 HCl [aq] → BeCl 2(aq] + H 2(g] ↑ Be (s] + 2 HCl [aq] → BeCl 2(aq] + H 2(g] ↑

To find the percent yield we have the formula

Percentage of Yield= what you actually get/ what you should theoretically get x 100

=3.5 g/0.45 g 100

= 777.78 %

The percentage of yield was 777.78%

5 0

3 years ago

815 yd to km (need 3 sig fig)

SpyIntel [72]

<u>Answer:</u> The correct answer is 0.745 km

<u>Explanation:</u>

We are given:

A numerical value of 815 yards

To convert this into kilometers, we use the conversion factor:

1 km = 1093.6 yards

Converting the given value into kilometers, we get:

$\Rightarrow 815yd\times \frac{1km}{1093.6yd}=0.745km$

Hence, the correct answer is 0.745 km

5 0

3 years ago

How many moles are in 3.24 x 1020 particles of lead? (show work plz)

lesya [120]

<h3>Answer:</h3>

0.000538 mol Pb

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right<u> </u>

<u>Chemistry</u>

<u>Atomic Structure</u>

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<u>Stoichiometry</u>

Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

3.24 × 10²⁰ particles Pb (lead)

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

Set up: $\displaystyle 3.24 \cdot 10^{20} \ particles \ Pb(\frac{1 \ mol \ Pb}{6.022 \cdot 10^{23} \ particles \ Pb})$
Multiply/Divide: $\displaystyle 0.000538 \ mol \ Pb$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 3 sig figs.</em>

Our final answer is in 3 sig figs, no need to round.

7 0

3 years ago

A solution is made by dissolving 10.7 g of magnesium sulfate, MgSO4, in enough water to make exactly 100 mL of solution. Calcula

adell [148]

Answer:

[MgSO₄] = 890 mM/L

Explanation:

In order to determine molarity we need to determine the moles of solute that are in 1L of solution.

Solute: MgSO₄ (10.7 g)

Solvent: water

Solution: 100 mL as volume. (100 mL . 1L / 1000mL) = 0.1L

We convert the solute's mass to moles → 10.7 g / 120.36 g/mol = 0.089 moles

Molarity (mol/L) → 0.089 mol/0.1L = 0.89 M

In order to calculate M to mM/L, we make this conversion:

0.89 mol . 1000 mmoles/ 1 mol = 890 mmoles

4 0

3 years ago