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2 years ago

Chemistry help!Zoom in to see better!!

Chemistry

1 answer:

Julli [10]2 years ago

4 0

Answer:

2.5 moles of Al

Explanation:

We'll begin by calculating the number of mole in 127 g of Al₂O₃. This can be obtained as follow:

Mass of Al₂O₃ = 127 g

Molar mass of Al₂O₃ = 101.961 g/mol

Mole of Al₂O₃ =?

Mole = mass / molar mass

Mole of Al₂O₃ = 127 / 101.961

Mole of Al₂O₃ = 1.25 mole

Finally, we shall determine the number of mole of Al that reacted. This can be obtained as follow:

4Al + 3O₂ —> 2Al₂O₃

From the balanced equation above,

4 moles of Al reacted to produce 2 moles of Al₂O₃.

Therefore, Xmol of Al will react to produce 1.25 moles of Al₂O₃ i.e

Xmol of Al = (1.25 × 4)/2

Xmol of Al = 2.5 moles.

Thus, 2.5 moles of Al is needed for the reaction.

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Mama L [17]

1)
-Lithium: Lithium got 3 protons, so it atomic number is 3. It is located on the first column of the periodic table, and belonging to the alkali metal. So lithium is a metal. Lithium is highly reactive.
-Neon: It is located on the 18th column of the periodic table, and belong to the noble gases. So Neon is a nonmetal. Neon's reactivity is very low.
-Fluorine: Located on the 17th column of the periodic metal, fluorine is a nonmetal, and belong to the halogen family. Fluorine's reactivity is high.

2)
-Vertical columns of the periodic table are called columns. There is 18 column in the periodic table, and each one represent a chemical family.
-Horizontal rows of the periodic table care called periods. There is 7 periods in the periodic table.
-The number of protons in an atom is that element's atomic number. And since the atom is electrically neutral, the number of protons is equal to the number of electrons. So if you have the number of electrons, you can still find the atomic number.
-The total of protons and neutrons in an atom is that element's atomic mass. Based on the formula A = Z + N, where A represents the atomic mass, Z the atomic number (number of protons) and N the number of neutrons.
-The elements in group 1 are the most reactive metals. This group is called the Alkali metals. They only have 1 electron in their outer shell which makes them always ready to lose an electron in an ionic bonding.
-The elements in group 17 are the most reactive nonmetals. This group is called the Halogens, with 7 electrons in their outer shell which makes them always ready to win an electron in an ionic bonding.
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Hope this Helps! :)

4 0

3 years ago

How many grams of lead(II) sulfate (303 g/mol) are needed to react with sodium chromate (162 g/mol) in order to produce 0.162 kg

Afina-wow [57]

Answer : The mass of $PbSO_4$ needed are, 1.515 grams.

Explanation :

First we have to calculate the mole of $PbCrO_4$ .

$\text{Moles of }PbCrO_4=\frac{\text{Mass of }PbCrO_4}{\text{Molar mass of }PbCrO_4}=\frac{0.162g}{323g/mole}=0.005mole$

Now we have to calculate the moles of $PbSO_4$ .

The balanced chemical reaction will be,

$PbSO_4+Na_2CrO_4\rightarrow PbCrO_4+Na_2SO_4[tex]From the balanced chemical reaction, we conclude thatAs, 1 mole of [tex]PbCrO_4$ produced from 1 mole of $PbSO_4$

So, 0.005 mole of $PbCrO_4$ produced from 0.005 mole of $PbSO_4$

Now we have to calculate the mass of $PbSO_4$

$\text{Mass of }PbSO_4=\text{Moles of }PbSO_4\times \text{Molar mass of }PbSO_4$

$\text{Mass of }PbSO_4=0.005mole\times 303g/mole=1.515g$

Therefore, the mass of $PbSO_4$ needed are, 1.515 grams.

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2 years ago

How does scientific method help scientists

Irina18 [472]

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3 years ago

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svlad2 [7]

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2 years ago

When a mixture of sulfur and metallic silver is heated, silver sulfide is produced. What mass of silver sulfide is produced from

IgorLugansk [536]

The question is incomplete, here is the complete question.

When a mixture of sulfur and metallic silver is heated, silver sulfide is produced. What mass of silver sulfide is produced from a mixture of 3.0g Ag and 3.0g $S_8$ .

Answer : The mass of silver sulfide is produced from a mixture is 3.44 grams.

Explanation : Given,

Mass of Ag = 3.0 g

Mass of $S_8$ = 3.0 g

Molar mass of Ag = 107.8 g/mole

Molar mass of $S_8$ = 256 g/mole

Molar mass of $Ag_2S$ = 247.8 g/mole

First we have to calculate the moles of Ag and $S_8$ .

$\text{ Moles of }Ag=\frac{\text{ Mass of }Ag}{\text{ Molar mass of }Ag}=\frac{3.0}{107.8g/mole}=0.0278moles$

$\text{ Moles of }S_8=\frac{\text{ Mass of }S_8}{\text{ Molar mass of }S_8}=\frac{3.0g}{256g/mole}=0.0117moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

$16Ag(s)+S_8(s)\rightarrow 8Ag_2S(s)$

From the balanced reaction we conclude that

As, 16 mole of $Ag$ react with 1 mole of $S_8$

So, 0.0278 moles of $Ag$ react with $\frac{0.0278}{16}=0.00174$ moles of $S_8$

From this we conclude that, $S_8$ is an excess reagent because the given moles are greater than the required moles and $Ag$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $Ag_2S$

From the reaction, we conclude that

As, 16 mole of $Ag$ react to give 8 mole of $Ag_2S$

So, 0.0278 moles of $Ag$ react to give $\frac{0.0278}{16}\times 8=0.0139$ moles of $Ag_2S$