Answer: fourth option, 10.8 kJ
Explanation:
The <em>heat of fusion</em>, also named latent heat of fusion, is the amount of heat energy required to change the state of a substance from solid to liquid (at constant pressure).
The data of the <em>heat of fusions</em> of the substances are reported in tables and they can be shown either per mole or per gram of substance.
In this case we have that the<em> heat of fusion for water </em>is reported per mole: <em>6.02 kJ/mole</em>.
The formula to calculate <em>how many kJ of heat (total heat) are needed to completely melt 32.3 g of water, given that the water is at its melting point</em> is:
- Heat = number of moles × heat of fusion
The calculations are:
- number of moles = mass / molar mass
number of moles = 32.3 g / 18.015 g/mol = 1.79 mol
- Heat = 1.79 mol × 6.02 kJ / mol = 10.8 kJ ← answer
When 1 mole of Zn and 2 mole of O₂ reacts togethor, It will produce 1 mole of ZnO as O₂ is excess reagent and Zn will act as Limiting reagent and thus it limits the amount of product formed.
<h3>What is Limiting reagent ?</h3>
Limiting reagents are the substances that are completely consumed first in a chemical reaction.
Given ;
- Amopunt of Zn : 1 mole
- Amount of O₂ : 2 mole
Given equation ;
2Zn + O₂ --> 2ZnO
As according to given chemical equation,
2 moles Zn of reacts with 1 mole of O₂ to produce 2 moles of ZnO.
Therefore,
1 mole of Zn will require 0.5 mole of O₂.
But,
the given amount of O₂ is 2 mole which is excess
Hence,
Zn here will act as the Limiting reagent, According to which the amount of product formed will be decided.
Therefore,
If 2 mole Zn produces : 2 moles of ZnO (According to given balanced equation)
Thus,
1 mole of Zn will produce = 2/2 x 1
= 1 mole of ZnO
Hence, When 1 mole of Zn and 2 mole of O₂ reacts togethor, It will produce 1 mole of ZnO as O₂ is excess reagent and Zn will act as Limiting reagent and thus it limits the amount of product formed.
Learn more about Limiting reagent here ;
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There are about 1.27 × 10^23 molecules present in 13.5 g of SO2.
<h3>What are molecules?</h3>
A molecule is the simplest part of a compound that have independent existence.
Number of moles of sulfur dioxide = 13.5 g/64 g/mol = 0.211 moles
If 1 mole of SO2 contains 6.02 × 10^23 molecules
0.211 moles of SO2 contains 0.211 moles × 6.02 × 10^23 molecules/1 mole
= 1.27 × 10^23 molecules
32 g of sulfur contains 6.02 × 10^23 atoms
x g of sulfur contains 2.23 x 10^23
x = 32 × 2.23 x 10^23 /6.02 × 10^23
x = 11.85 g
6.02 × 10^23 formula units has a mass of AgF = 127 g
x formula units has a mass of = 42.15 g
x = 6.02 × 10^23 × 42.15/127
x = 2 × 10^23 formula units
6.02 × 10^23 formula units of Fe2O3 has a mass of 160 g
8.83 x 10^23 formula units of Fe2O3 has a mass of 8.83 x 10^23 x 160 g/6.02 × 10^23
x = 235 g
Learn more about formula unit: brainly.com/question/19293051
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