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3 years ago

Why does a chemical equation have to be balanced

Chemistry

1 answer:

Anton [14]3 years ago

5 0

The chemical equation needs to be balanced so that it follows the law of conservation of mass.

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A sample of nitric acid has a mass of 8.2g. It is dissolved in 1L of water. A 25mL aliquot of this acid is titrated with NaOH. T

AveGali [126]

Answer:

18.075 mL of NaOH solution was added to achieve neutralization

Explanation:

First, let's formulate the chemical reaction between nitric acid and sodium hydroxide:

NaOH + HNO3 → NaNO3 + H2O

From this balanced equation we know that 1 mole of NaOH reacts with 1 mole of HNO3 to achieve neutralization. Let's calculate how many moles we have in the 25 mL aliquot to be titrated:

63.01 g of HNO3 ----- 1 mole

8.2 g of HNO3 ----- x = (8.2 g × 1 mole)/63.01 g = 0.13014 moles of HNO3

So far we added 8.2 grams of nitric acid (0.13014 moles) in 1 L of water.

1000 mL solution ---- 0.13014 moles of HNO3

25 mL (aliquot) ---- x = (25 mL× 0.13014 moles)/1000 mL = 0.0032535 moles

So, we now know that in the 25 mL aliquot to be titrated we have 0.0032535 moles of HNO3. As we stated before, 1 mole of NaOH will react with 1 mole of HNO3, hence 0.0032535 moles of HNO3 have to react with 0.0032535 moles of NaOH to achieve neutralization. Let's calculate then, in which volume of the given NaOH solution we have 0.0032535 moles:

0.18 moles of NaOH ----- 1000 mL Solution

0.0032535 moles---- x=(0.0032535moles×1000 mL)/0.18 moles = 18.075mL

As we can see, we need 18.075 mL of a 0.18 M NaOH solution to titrate a 25 mL aliquot of the prepared HNO3 solution.

4 0

2 years ago

Find the mass of oxygen in grams produced by the decomposition of 100.0 g of CO2

SSSSS [86.1K]

The balanced chemical equation is :

$2CO_2->2CO+O_2\\\\$

Moles of $CO_2$ ,

$n = \dfrac{100\ g}{44.01\ g/mol}\\\\n=2.27\ mol$

Now, by given chemical equation , we can see 2 mole of $CO_2$ react with 1 mole of $O_2$ .

So , 2.27 mole react with :

$N=\dfrac{2.27}{2}\ mol\\\\N=1.135\ mol$

Mass of oxygen is :

$M = N \times 16\\\\M=1.135\times 16\ g\\\\M =18.16\ g$

Therefore, mass of oxygen in grams produced is 18.16 g.

Hence, this is the required solution.

7 0

3 years ago

Explain how an automobile air bag protects the people in the car from being hurt as a result of impact

liraira [26]

The quick deployment of the bag which I think is quite similar to a cushion and a balloon. It holds your head/face away from any hard surfaces. Although it does not protect your legs or other extremities that are out of the bags range.

5 0

2 years ago

How many moles of KOH are required to produce 4.79 g K3PO4 according to the following reaction? 3KOH + H3PO4 -----> K3PO4 + 3

8_murik_8 [283]

Answer:

0.677 moles

Explanation:

Take the atomic mass of K = 39.1, O =16.0, P = 31.0

no. of moles = mass / molar mass

no. of moles of K3PO4 used = 4.79 / (39.1x3 + 31 + 16x4)

= 0.02256 mol

From the equation, the mole ratio of KOH : K3PO4 = 3 :1,

meaning every 3 moles of KOH used, produces 1 mole of K3PO4.

So, using this ratio, let the no. of moles of KOH required to be y.

$\frac{3}{1} =\frac{y}{0.02256} \\$

y = 0.02256 x3

y = 0.0677 mol

If you don't find exactly 0.677 moles as one of the options, go for the closest one. A very slight error may occur because of taking different significant figures of atomic masses when calculating.

5 0

3 years ago

Select True or False: Hydrogen plays an important role in many industrial processes. The following correctly represents a balanc

Orlov [11]

Answer: False

Explanation:

Since the given equation is not balanced properly.

Since oxygen and hydrogen atoms are not balanced.

There should be 6 H2O (g) molecules and 14 mol H2 (g)

5 0

2 years ago