<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
<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:
- [DA] Multiply/Divide [Cancel out units]:
<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
The molecular weight of Mg(OH)2 : 58 g/mol
<h3>Further explanation</h3>
Given
Mg(OH)2 compound
Required
The molecular weight
Solution
Relative atomic mass (Ar) of element : the average atomic mass of its isotopes
Relative molecular weight (M) : The sum of the relative atomic mass of Ar
M AxBy = (x.Ar A + y. Ar B)
So for Mg(OH)2 :
= Ar Mg + 2 x Ar O + 2 x Ar H
= 24 g/mol + 2 x 16 g/mol + 2 x 1 g/mol
= 24 + 32 + 2
= 58 g/mol
Answer:
D.Salad
Explanation:
A mixture is a substance that combines two or more substance that are physically combined. A mixture can be easily seperated by a physical means . A mixture is the combination of various substances that are not chemically combined .Examples of mixtures are cake and salad . The cake contains various substances like egg, flour and sugar. This mixture can be easily separated into it individual entities by a physical means .
Base on the option the only mixture among the option is salad . Salad is a a mixtures that combines substances like tomatoes , fruits and vegetable. The individual substances that makes up the salad can be easily separated.
Sugar is a compound . Water is a compound as it contains two elements and potassium is an element.
Answer:
A pure substance has a definite chemical composition
Answer:
The given statement is true.
Explanation:
The given statement is true.
As per an estimate, to convert graphite into diamond nearly 1 billion to 3.3 billion years of time is required.
Graphite converts into diamond when high-pressure is applied deep in the earth core.
