<h3>
Answer:</h3>
3.01 × 10²⁵ molecules H₂O
<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>
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
50.0 mol H₂O
<u>Step 2: Identify Conversions</u>
Avogadro's Number
<u>Step 3: Convert</u>
<u />
= 3.011 × 10²⁵ molecules H₂O
<u>Step 4: Check</u>
<em>We are given 3 sig figs. Follow sig fig rules and round.</em>
3.011 × 10²⁵ molecules H₂O ≈ 3.01 × 10²⁵ molecules H₂O
Answer: AIP
There are two types of substances mixture and pure substance. Mixture has NO chemical formula and a pure substance has a chemical formula. There are two types of pure substances, elements (mono atomic and molecular) and compounds ( covalent and ionic).
Ionic compounds do not exist in independent molecular form. They form three dimensional crystal lattice, in which each ion is surrounded by oppositely charged ion. so the ratio of ion is called the formula unit
Answer;
A) Stage 1: Chlorophyll captures light energy. Stage 2: Light energy is converted to chemical energy.
Explanation;
-Photosynthesis is the process by which green plants use energy from the sun, water and carbon dioxide to make organic compounds such as simple sugars together with release of oxygen.
-The process occurs in tow stages; light-dependent stage and light independent stage. During light dependent stage, chlorophyll absorbs sunlight and uses it to split water molecules into hydrogen ions and oxygen atoms. In the light independent stage carbon (iv) dioxide is fixed and the result is organic compound; the light energy is converted to chemical energy.
First a balanced reaction equation must be established:

→

Now if mass of aluminum = 145 g
the moles of aluminum = (MASS) ÷ (MOLAR MASS) = 145 g ÷ 30 g/mol
= 4.83 mols
Now the mole ratio of Al : O₂ based on the equation is 4 : 3
[
4Al +
3 O₂ → 2 Al₂O₃]
∴ if moles of Al = 4.83 moles
then moles of O₂ = (4.83 mol ÷ 4) × 3
=
3.63 mol (to 2 sig. fig.)
Thus it can be concluded that
3.63 moles of oxygen is needed to react completely with 145 g of aluminum.