Answer:
20.5 × 10²³ molecules of He
Explanation:
Given data:
Number of moles of He = 3.40 mol
Number of molecules of He = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 3.40 moles of He:
3.40 mol × 6.022 × 10²³ molecules
20.5 × 10²³ molecules of He
The percentage yield of the new production technique is 82.8%
<h3>What is the percentage yield?</h3>
Production is the procedure by which finished products are obtained form the raw materials. The production process involves the passing of raw materials through a certain procedure that involves the use of certain machines and equipment to give us the required products.
We are told in the question that there are three shifts;
Shift 1 produces 4562 grams
Shift 2 produces 5783 grams
Shift 3 produces 5247 grams
Average production from the three shifts = 4562 grams + 5783 grams + 5247 grams/3 = 5197 grams
The theoretical average yield is = 7000 grams + 7000 grams + 7000 grams/3 = 7000 grams
Now the percentage yield = actual yield/ theoretical yield * 100/1
percentage yield = 5197 grams/7000 grams * 100/1
percentage yield = 82.8%
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Answer:
+2
Explanation:
Alkaline earth metals are present in group 2 of periodic table. There are six elements in second group. Beryllium, magnesium, calcium, strontium, barium and radium.
All have two valance electrons.
Electronic configuration of Beryllium:
Be = [He] 2s²
Electronic configuration of magnesium.
Mg = [Ne] 3s²
Electronic configuration of calcium.
Ca = [Ar] 4s²
Electronic configuration of strontium.
Sr = [Kr] 5s²
Electronic configuration of barium.
Ba = [Xe] 6s²
Electronic configuration of radium.
Ra = [ Rn] 7s²
They are present in group two and have same number of valance electrons (two valance electrons) and show oxidation state +2 by loosing two valance electrons. They also show similar reactivity.
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
Explanation:
vraiLe point d'ébullition est la température à laquelle une substance passe de la phase liquide à la phase gazeuse
It's A; decomposition reactions involve one reactant becoming 2 or more products.
