A pencil is 7 in Long what is its length in centimeters
1 answer:
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Given parameters:
Mass of KClO₃ = 125g
Unknown:
Total mass of the products = ?
When KClO₃ is heated, it thermally decomposes to KCl and O₂ according to the chemical equation below;
2KClO₃ → 2KCl + 3O₂
All chemical equations obeys the law of conservation of matter and with this regard, we know that the amount of reactants used is the same as that of the product.
The total mass of the products must give us 125g according to this law of conservation of matter.
Now to find the masses of each product,
- Find the number of moles of the given reactant:
Number of moles =
molar mass of KClO₃ = 39 + 35.5 + 3(16) = 122.5g/mol
So number of moles of KClO₃ = = 1.02moles
2. Now, using this number of moles, find the number of moles of the products using this value;
2 moles of KClO₃ produced 2 moles of KCl
1.02 moles of KClO₃ will also produce 1.02moles of KCl
2 moles of KClO₃ produced 3 moles of O₂
1.02 moles of KClO₃ will produce mole = 1.53 moles of O₂
3. Now find the masses of each product;
Mass = number of moles x molar mass
molar mass of KCl = 39 + 35.5 = 74.5g/mol
molar mass of O₂ = 16 x 2 = 32g/mol
Mass of KCl = 74.5 x 1.02 = 75.99g
Mass of O₂ = 32 x 1.53 = 48.96g
Total mass of products = mass of KCl + Mass of O₂ = 75.99g + 48.96g
= 124.95g
This value is approximately the same as that of mass of KClO₃
Answer:
3.01 × 10²⁴ atoms S
General Formulas and Concepts:
<u>Chemistry - Atomic Structure</u>
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Explanation:
<u>Step 1: Define</u>
5.00 mol S
<u>Step 2: Identify Conversions</u>
Avogadro's Number
<u>Step 3: Convert</u>
<u /> = 3.011 × 10²⁴ atoms S
<u />
<u>Step 4: Check</u>
<em>We are given 3 sig figs. Follow sig fig rules and round.</em>
3.011 × 10²⁴ atoms S ≈ 3.01 × 10²⁴ atoms S
Answer:
- Question 19: the three are molecular compounds.
- Question 20: CuSO₄.5H₂O
Explanation:
<em>Question 19.</em>
- C₂H₄
- HF
- H₂O₂
All of them are the combination of two kinds of different atoms in fixed proportions.
- C₂H₄: two carbon atoms per four hydrogen atoms
- HF: one hydrogen atom per one fluorine atom
- H₂O₂: two hydrogen atoms per two oxygent atoms
Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.
Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.
Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.
<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.
Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol
Water is H₂O. Its molar mass is 18.015g/mol
Calling x the number of water molecules in the hydrate, the percentage of water is:
From which we can solve for x:
Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:
- CuSO₄.5H₂O