What do tissues combine to form?

How many moles are in 7.2x10^15 atoms of Pb?

fiasKO [112]

<h3>Answer:</h3>

1.2 × 10⁻⁸ 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>

[Given] 7.2 × 10¹⁵ atoms Pb

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

Avogadro's Number

<u>Step 3: Convert</u>

[DA] Set up: $\displaystyle 7.2 \cdot 10^{15} \ atoms \ Pb(\frac{1 \ mol \ Pb}{6.022 \cdot 10^{23} \ atoms \ Pb})$
[DA] Multiply/Divide [Cancel out units]: $\displaystyle 1.19562 \cdot 10^{-8} \ mol \ Pb$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 2 sig figs.</em>

1.19562 × 10⁻⁸ mol Pb ≈ 1.2 × 10⁻⁸ mol Pb

6 0

2 years ago

I have my chemistry EOC tomorrow, and I need to know how to calculate the molar mass of a compound. Specifically ones set up lik

yuradex [85]

Answer:

357.475

Explanation:

First you need periodic table and you have to look for mass

Fe = 3 x 55.845 = 167.535

P = 2 x 30.97 = 61.94

o = 4 x 2 so 8 oxygen = 8 x 16 = 128

add all and you get 357.475

6 0

2 years ago

Several bird species feed is a certain species of tree. Each bird species feeds in a different part of the tree. Which statement

Fofino [41]

Answer:

They have adapted to different niches.

Explanation:

due to competition

8 0

3 years ago

Read 2 more answers

A 150.0mL sample of an aqueous solution at 25C contains 15.2mg of an unknown nonelectrolyte compound. If the solution has an osm

Nookie1986 [14]

Answer:

MM = 225.11 g/mol

Explanation:

In this case, let's analyze the data.

We have a 15.2 mg of an unknown electrolyte in 150 mL of solution. The osmotic pressure is 8.44 Torr, and we want the molecular mass of the unknown.

The osmotic pressure can be calculated using the following expression:

π = CRT (1)

π: osmotic pressure (8.44 Torr * 1 atm / 760 Torr = 0.011 atm)

C: Concentration of the unknown in the solution

R: universal constant of gases (0.082 L atm / K mol)

T: temperature in Kelvin (25 + 273 = 298 K)

From this expression, we can either solve for C, and then use another expression to calculate the molecular mass, or we can just replace the expressions in the above formula, to get the direct molecular mass. In this case, we'll follow the second method.

Concentration or molarity of a substance can be calculated using:

C = moles / V (2)

And moles can be calculated using this expression:

moles = m / MM (3)

Replacing (3) in (2), and then in (1) we have:

C = m / MM * V

π = m * RT / MM * V (4)

and now, we can solve for MM:

MM = mRT / π V (5)

Now, we just need to replace the given data into the above expression to get the value of the molecular mass:

MM = (15.2 / 1000) * 0.082 * 298 / 0.011 * 0.150

Hope this helps

3 0

3 years ago

.

Darina [25.2K]

Answer:

C

Explanation:

4× CH2 = C4H8

7 0

2 years ago