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3 years ago

What about these questions

Chemistry

1 answer:

Oksanka [162]3 years ago

4 0

Again great job! They all look correct except 20. is 3.7 due to sig fig of least precision, which you have a mark by!! You don't even need help!;) Here comes the next chemical engineer! :)

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Fill in the chart to describe and give examples of physical changes.

frosja888 [35]

Answer:

here are some examples of physical change!!!

Explanation:

-An ice cube melting into water in your drink.

-Freezing water to make ice cubes.

-Boiling water evaporating.

-Hot shower water turning to steam.

-Steam from the shower condensing on a mirror.

8 0

2 years ago

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What is the atomic weight of potassium

frosja888 [35]

39.0983 u ± 0.0001 u

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2 years ago

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Identify 6 examples of weathering (mechanical, chemical) in your environment such as (household, yard, street, cemetery, park, a

Bogdan [553]

Chemical weathering is when things get weathered chemically

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3 years ago

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Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form magnesium chloride and iron. A mixtur

yuradex [85]

Answer: The limiting reactant is magnesium and mass of excess reactant present in the vessel is 96.35 grams.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For magnesium:

Given mass of magnesium = 41.0 g

Molar mass of magnesium = 24 g/mol

Putting values in equation 1, we get:

$\text{Moles of magnesium}=\frac{41.0g}{24g/mol}=1.708mol$

For iron(III) chloride:

Given mass of iron(III) chloride = 175.0 g

Molar mass of iron(III) chloride = 162.2 g/mol

Putting values in equation 1, we get:

$\text{Moles of iron(III) chloride}=\frac{175g}{162.2g/mol}=1.708mol$

The chemical equation for the reaction of magnesium and iron(III) chloride follows:

$3Mg+2FeCl_3\rightarrow 3MgCl_2+2Fe$

By Stoichiometry of the reaction:

3 moles of magnesium reacts with 2 moles of iron(III) chloride

So, 1.708 moles of magnesium will react with = $\frac{2}{3}\times 1.708=1.114mol$ of iron(III) chloride

As, given amount of iron(III) chloride is more than the required amount. So, it is considered as an excess reagent.

Thus, magnesium is considered as a limiting reagent because it limits the formation of product.

Moles of excess reactant left (iron(III) chloride) = [1.708 - 1.114] = 0.594 moles

Now, calculating the mass of iron(III) chloride from equation 1, we get:

Molar mass of iron(III) chloride = 162.2 g/mol

Moles of iron(III) chloride = 0.594 moles

Putting values in equation 1, we get:

$0.594mol=\frac{\text{Mass of iron(III) chloride}}{162.2g/mol}\\\\\text{Mass of iron(III) chloride}=(0.594mol\times 162.2g/mol)=96.35g$

Hence, the limiting reactant is magnesium and mass of excess reactant present in the vessel is 96.35 grams.

6 0

3 years ago

A mover packs books, CDs, and DVDs into a moving box. If the box contains 6.5 kg of books, 1.5 kg of CDs, and 2.0 kg of DVDs, wh

IrinaVladis [17]

Answer:

$\text{Mass percentage}=\frac{\text{Mass of the substance}}{\text{Total mass}}\times 100$

Given: Mass of books = 6.5 kg

Mass of CD's = 1.5 kg

Mass of DVD's = 2.0 kg

Total mass = 6.5 kg + 1.5 kg + 2.0 kg = 10 kg

$\text {Mass percentage of books}=\frac{6.5kg}{10kg}\times {100}=65\%$

$\text {Mass percentage of CD's}=\frac{1.5kg}{10kg}\times {100}=15\%$

$\text {Mass percentage of DVD's}=\frac{2.0kg}{10}\times {100}=20\%$

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3 years ago

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