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3 years ago

1. Working in the laboratory, a student find the density of a piece of pure aluminum to be 2.85

Chemistry

1 answer:

dsp733 years ago

4 0

Answer:

5.59 %

Explanation:

From the question given above, the following data were obtained:

Observed value of density = 2.85 g/cm³

True value of density = 2.699 g/cm³

Percentage error =.?

The percentage error of the student can be obtained as follow:

Percentage error = |Observed value – True value|/True value × 100

Percentage error = |2.85 – 2.699|/2.699

Percentage error = 0.151/2.699 × 100

Percentage error = 5.59 %

Therefore, the percentage error of the student is 5.59 %.

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4 moles of hydrogen react with 5 moles of oxygen to form water, identify the excess reagent?

Fynjy0 [20]

Answer:

Excess Reagent = oxygen

Explanation:

Limiting reagent: The substance that is totally consumed when the reaction is completed.

Excess reagent: The substance left after the limiting reagent is consumed completely

The balanced chemical equation for formation of water is as follow:

$2H_{2}+O_{2}\rightarrow 2H_{2}O$

This means when 2 moles of hydrogen reacts with 1 mole of oxygen, 2 moles of water is produced.

Hence the ratio in which hydrogen and oxygen gas reacts is 2:1

Now if 2 mole hydrogen require 1 mole of oxygen ,then 4 mole hydrogen need 2 mole of oxygen.

$H_{2}:O_{2}=2:1$

$H_{2}:O_{2}=4:2$

Here 5 mole of oxygen is reacting but only 2 mole is required .

Oxygen is in excess.

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3 years ago

The seasons are caused by

azamat

Answer:

The seasons are caused by the tilt of the Earth's rotational axis away or toward the sun as it travels through its year-long path around the sun

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4 years ago

Read 2 more answers

Sulfuric acid dissolves aluminum metal according to the following reaction:

Fiesta28 [93]

Answer:

$m_{H_2SO_4}=81.7gH_2SO_4$

$m_{H_2}=1.67gH_2$

Explanation:

Hello,

Based on the given undergoing chemical reaction is is rewritten below:

$2Al (s) + 3H_2SO_4 (aq)\rightarrow Al _2(SO4)_3 (aq) + 3H_2 (g)$

By stoichiometry we find the minimum mass of H2SO4 (in g) as shown below:

$m_{H_2SO_4}=15.0gAl*\frac{1molAl}{27gAl}*\frac{3molH_2SO_4}{2molAl}*\frac{98gH_2SO_4}{1molH_2SO_4} \\m_{H_2SO_4}=81.7gH_2SO_4$

Moreover, mass of H2 gas (in g) would be produced by the complete reaction of the aluminum block turns out:

$m_{H_2}=15.0gAl*\frac{1molAl}{27gAl}*\frac{3molH_2}{2molAl}*\frac{2gH_2}{1molH_2} \\m_{H_2}=1.67gH_2$

Best regards.

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3 years ago

Which of the following is NOT a type of pseudoscience?

s344n2d4d5 [400]

The answer is C. SETI

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3 years ago

Write the balanced chemical equation between H2SO4 and KOH in aqueous solution. This is called a neutralization reaction and wil

emmainna [20.7K]

Answer:

0.166M

Explanation:

In a neutralization, the acid, H₂SO₄, reacts with a base, KOH, to produce a salt, K₂SO₄ and water. The reaction is:

H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O

To solve this problem, we need to determine moles of H2SO4 and moles of KOH that reacts to find the moles of sulfuric acid that remains after the reaction:

<em>Moles H2SO4:</em>

0.650L * (0.430mol /L) = 0.2795moles H2SO4

<em>Moles KOH:</em>

0.600L * (0.240mol / L) = 0.144 moles KOH

Moles of sulfuric acid that reacts with 0.144 moles of KOH are:

0.144 moles KOH * (1mol H2SO4 / 2 mol KOH) = 0.072 moles of H2SO4 react.

And remain:

0.2795moles H2SO4 - 0.072moles H2SO4 = 0.2075 moles of H2SO4 reamains.

In 0.650L + 0.600L = 1.25L:

Molar concentration of sulfuric acid:

0.2075 moles of H2SO4 / 1.25L =

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3 years ago