True or False - when setting up your conversion problems every numerical value must have a unit on it.

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>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Atomic Structure

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

Stoichiometry

Using Dimensional Analysis

<h3>Explanation:</h3>

Step 1: Define

[Given] 7.2 × 10¹⁵ atoms Pb

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

[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]: $\displaystyle 1.19562 \cdot 10^{-8} \ mol \ Pb$

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

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

6 0

2 years ago

Calculate the net force 175 N 1125 N

Ket [755]

Answer:

<h3>_____________&_________</h3><h2>Net force = sum of all forces with directions</h2><h2>so.....</h2><h2>NET FORCE = 125+(-75)</h2><h2> = 50 N</h2><h2> in the direction of yellow </h2><h2> t-shirt man</h2><h2>------------------------------------</h2>

4 0

3 years ago

Plz answer asap !!!!

Semmy [17]

Answer:it's c

Explanation:

..

6 0

3 years ago

Which energy transformation is taking place when an animal eats food so it can keep warm

Elenna [48]

Radiant energy to thermal energy

6 0

3 years ago

Balance this eqaution:

klasskru [66]

Answer:

H₂ + CuO → Cu + H₂O

Explanation:

We want to balance the given equation;

H₂ + CuO → Cu(OH)₂ + H₂O

To balance this we have to make sure the number of each element on the left is equal to the number of each element on the right.

Thus, the correct balanced equation is;

H₂ + CuO → Cu + H₂O

5 0

2 years ago