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4 years ago

One of the most common elements is Oxygen.

Chemistry

1 answer:

nata0808 [166]4 years ago

4 0

Answer:

Explanation:

- The atomic number of Oxygen is 8.

- The relative atomic mass is approximately 16.

- It has 8 number of protons.

- It has 8 number of neutrons ( Atomic Mass - number of protons).

- Oxygen has 6 valence electrons.

- It has 2 energy shells, two electrons occupy the first energy shell while six electrons occupy the second energy shell.

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An Arrhenius acid has

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The answer is (3) hydrogen ions as the only positive ions in solution. One ionic compound must have positive ion and negative ion at the same time. The Arrhenius base has hydroxyl ion as only negative ions in solution.

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3 years ago

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I need the amount of rain in tundra

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6- 10 inches of rain a year.

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3 years ago

A laser light was shone through a diffraction grating whose lines were 1/1000 mm apart. The distance was measured between the ce

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3 years ago

Many computer chips are manufactured from silicon, which occurs in nature as SiO2. When SiO2 is heated to melting, it reacts wit

Mariulka [41]

Answer:

(a): The theoretical yield of silicon is 72.33 kg.

(b): The percent yield of the reaction is 91.25 %.

Explanation:

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

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

For $SiO_2$ :

Given mass = 155.0 kg = 155000 g (Conversion factor: 1 kg = 1000 g)

Molar mass = 60 g/mol

Putting values in equation 1:

$\text{Moles of }SiO_2=\frac{155000g}{60g/mol}=2583.3mol$

For carbon:

Given mass = 78.2 kg = 78200 g

Molar mass = 12 g/mol

Putting values in equation 1:

$\text{Moles of carbon}=\frac{78200g}{12g/mol}=6516.67mol$

The chemical equation for the reaction of silicon dioxide and carbon follows:

$SiO_2+2C\rightarrow Si+2CO$

By stoichiometry of the reaction:

1 mole of $SiO_2$ reacts with 2 moles of carbon

So, 2583.3 moles of $SiO_2$ will react with = $\frac{2}{1}\times 2583.3=5166.4mol$ of carbon

As the given amount of carbon is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, $SiO_2$ is considered a limiting reagent because it limits the formation of the product.

For (a):

By stoichiometry of the reaction:

1 mole of $SiO_2$ produces 1 mole of silicon

So, 2583.3 moles of $SiO_2$ will produce = $\frac{1}{1}\times 2583.3=2583.3mol$ of silicon

Since the molar mass of silicon = 28 g/mol

Putting values in equation 1:

$\text{Mass of Si}=2583.3mol\times 28g/mol=72332.4g=72.33 kg$

Hence, the theoretical yield of silicon is 72.33 kg.

For (b):

The percent yield of a reaction is calculated by using an equation:

$\% \text{yield}=\frac{\text{Measured value}}{\text{Theoretical value}}\times 100$ ......(2)

Given values:

Measured value of silicon = 66.0 kg

Theoretical value of silicon = 72.33 kg

Putting values in equation 1:

$\% \text{yield}=\frac{66.0kg}{72.33kg}\times 100\\\\\% \text{yield}=91.25 \%$

Hence, the percent yield of the reaction is 91.25 %.

3 0

3 years ago

What is the average mass of fruit purchased in lb

Vera_Pavlovna [14]

Answer:

so first what you would do is the first questions asking what is the average mass of the fruits! so in my head im looking at the graph and go i would add up all the fruits MASS make sure to add the mass only and get the total of the mass that all the fruits have. the seconed question is asking what is the average cost of the first purchase? look at the graph it says the first fruit cost 1.37 dollars. the third and last question is calculate the average cost per mass of the fruit purchassed. so this is a tricky one but ill help you what i think would take the cost of the fruit and divide it by the mass of each fruit! i hope tis helps you can do this! i can also say that question two is trying to make you think over it so dont its litteraly stated to you on the graph lol

Explanation:

7 0

3 years ago