40 watts because 120-80 is forty or 80 + 40 - 120
<em>ANSWER</em>
The number of moles of methane is 905.32 moles
STEP-BY-STEP EXPLANATION:
Given information
The number of particles of methane = 5.45 x 10^26 particles
Let x represents the number of moles of methane
To calculate the number of moles, we will be using the below formula
Recall that, the Avogadro's constant is given as
Therefore, the number of moles of methane is 905.32 moles
Answer:
3.18 (w/w) %
Explanation:
In the problem, you can find mass of NaClO knowing the reaction of NaClO with Na₂S₂O₃ is:
NaClO + 2Na₂S₂O₃ + H₂O → NaCl + Na₂S₄O₆ +2NaOH + NaCl
<em>Where 1 mole of NaClO reacts with 2 moles of Na₂S₂O₃</em>
<em> </em>Moles of thiosulfate in the titration are:
0.0101L ₓ (0.042mol / L) = 4.242x10⁻⁴ moles of Na₂S₂O₃
Thus, moles of NaClO in the initial solution are:
4.242x10⁻⁴ moles of Na₂S₂O₃ ₓ (1mol NaClO / 2 mol Na₂S₂O₃) = 2.121x10⁻⁴ moles NaClO
As molar mass of NaClO is 74.44g/mol, mass of 2.121x10⁻⁴ moles are:
2.121x10⁻⁴ moles ₓ (74.44g / mol) = <em>0.0158g of NaClO</em>
As mass of bleach is 0.496g, mass percent is:
0.0158g NaClO / 0.496g bleach ₓ 100 =
<h3>3.18 (w/w) % </h3>
The mass of reacted magnesium chloride is 23.75g, percent by mass of solution magnesium chloride is 90.9%.
<h3>What is the relation between mass & moles?</h3>
Relation between the mass and moles of any substance will be represented as:
n = W/M, where
- W = given mass
- M = molar mass
Moles of MgCl₂ = 200g / 95g/mol = 2.1mol
Moles of NaOH = 20g / 0.5mol
Given chemical reaction is:
MgCl₂ + 2NaOH → 2NaCl + Mg(OH)₂
From the stoichiometry of the reaction it is clear that
- 1 mole of MgCl₂ = reacts with 2 moles of NaOH
- 0.5 mole of NaOH = reacts with (1/2)(0.5)=0.25 moles of MgCl₂
Mass of reacted MgCl₂ = (0.25mol)(95g/mol) = 23.75g
Percent by mass of MgCl₂ in the given solution mixture will be calculated as:
- % by mass = (Mass of MgCl₂ / Total mass of mixture) × 100%
- Percent by mass of MgCl₂ = (200/200+20)×100% = 90.0&
In the above reaction we obtain NaCl as a solid, and MgCl₂ is the limiting reagent in it, from which 2 moles of NaCl is produced means
- 0.25 moles of MgCl₂ = produces 0.5 moles of NaCl
Mass of NaCl = (0.5mol)(58.5g/mol) = 29.25g
Hence, mass of reacted MgCl₂ is 23.75g, percent by mass of solution magnesium chloride is 90.9% and mass of the obtained solid is 29.25g.
To know more about mass & moles, visit the below link:
brainly.com/question/20838755
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