Hey there!:
Molar mass Lead ( Pb ) = 207.2 g/mol
Therefore:
1 mole Pb --------------------- 6.02*10²³ atoms
? moles Pb -------------------- 2.31*10²¹ atoms
moles Pb = ( 2.31*10²¹ ) * 1 / ( 6.02*10²³ ) =
moles Pb = ( 2.31*10²¹ ) / ( 6.02*10²³ ) =
=> 0.00383 moles of Pb
Hope this helps !
Salt crystals are shaped like cubes. Salt is part of the isometric crystal system.
Answer:
Explanation:
Iodine - 125
The atomic symbol of iodine is ¹²⁵₅₃ I
The symbol for iodine is I
The atomic number of iodine is 53,
and the atomic mass of iodine is 125 .
<u>The representation of the atomic symbol is as, the atomic mass is written in uppercase and the atomic number is written in lower case , followed by the symbol of the element .</u>
Iodine is a radio active element , used for many biological process .
It is the second largest -lived radioisotope of iodine .
The first is iodine-129 .
Answer:
chemical change it is melted down
<h3>
Answer:</h3>

<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Stoichiometry</u>
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
[RxN - Balanced] 2Al₂O₃ → 4Al + 3O₂
[Given] 20 mol Al₂O₃
<u>Step 2: Identify Conversions</u>
[RxN] 2 mol Al₂O₃ → 4 mol Al
<u>Step 3: Stoich</u>
- [DA] Set up:

- [DA] Multiply/Divide [Cancel out units]:

<u>Step 4:Check</u>
<em>Follow sig fig rules and round. We are given 1 sig fig.</em>
Since our final answer already has 1 sig fig, there is no need to round.