Answer:You can get the valence electrons in an atom's electronic arrangement by consulting the periodic table:
Explanation:
The Group 1 atoms have 1 valence electron.
The Group 2 atoms have 2 valence electrons.
The Group 3 atoms have 3 valence electrons.
The Group 4 atoms have 4 valence electrons.
Stardust atoms are heavier elements, the percentage of star mass in our body is much more impressive. Most hydrogen in our body floats around in the form of water .
Answer:
18.58 moles of Cu
Solution:
Data Given:
Chemical Formula of Tennantite = Cu₁₂As₄S₁₃
Mass of Cu₁₂As₄S₁₃ = 2290 g
M.Mass of Cu₁₂As₄S₁₃ = 1479.06 g.mol⁻¹
Step 1: Calculate Moles of Cu₁₂As₄S₁₃ as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 2290 g ÷ 1479.06 g.mol⁻¹
Moles = 1.548 mol
Step 2: Calculate Moles of Cu,
As,
1 mole of Cu₁₂As₄S₁₃ contains = 12 moles of Cu
So,
1.548 mol of Cu₁₂As₄S₁₃ will contain = X moles of Cu
Solving for X,
X = (1.548 mol × 12 mol) ÷ 1 mol
X = 18.58 moles of Cu
Explanation:
Given parameters:
Mass of sample = 235g
Molecular mass of sample = 128.1g
Empirical formula = CH₂O
Unknown:
Mass of each element in the sample = ?
Solution:
To solve this problem, we must know that the empirical formula of any compound is the simplest ratio of the atoms it contains. This is not the true formula of the compound.
Molecular formula = (Empirical formula)ₙ
Let us find the molecular mass of the sample;
CH₂O = 12 + 2(1) + 16 = 30g
128.1 = (30)n
n = 4
The molecular formula of the compound is; (CH₂O)₄ = C₄H₈O₄
Now to find the grams of each element in the sample;
Express the molecular mass of each element and that of the compound as a fraction and multiply with the given mass;
For C;
= 88.06g
H; 
= 14.68g
O: 
= 117.41g
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Mass composition brainly.com/question/3018544
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Balanced equation:
<span>2 NO + 5 H2 ------> 2 NH3 + 2 H2O
</span>
<span>2 moles NO react with 5 moles H2 to produce 2 moles NH3
</span>
<span>Molar mass of NO = 30.00 g/mol </span>
<span>86.3g NO = 86.3/30.00 = 2.877 moles of NO </span>
<span>This will require: 2.877*5 / 2 = 7.192 moles of H2 </span>
<span>Molar mass of H2 = 2 g/mol </span>
<span>25.6g H2 = 25.6/2 = 12.7 mol H2. </span>
<span>You have excess H2 means the NO is limiting </span>
<span>From the balanced equation: </span>
<span>2 moles of NO will produce 2 moles of NH3 </span>
<span>2.877 moles of NO will produce 2.877 moles of NH3 </span>
<span>Molar mass NH3 = 17g/mol </span>
<span>Mass NH3 produced = 2.877 * 17 = 48.91g
Hence the yield is = 48.91 g ~ 49 g</span>
