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4 years ago

How are parentheses used in chemical formulas

2 answers:

8 0

In a chemical compound, parenthesis are used to distinguish the number of polyatomic ions from the number of atoms. Such as in the compound calcium nitrate, it is written as $Ca(NO_{3} ) _{2}$ . This means there are two nitrate ions for every one calcium ion.

Zarrin [17]4 years ago

3 0

it is meant to distinguish the number of polyatomic ions from the number of atoms in a given polyatomic ion. an example is Ca(NO3)2

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lions [1.4K]

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F/a = m
(25 N) / (5 m/s2) = m
4 kg = m

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3 years ago

Automobile air bags use the decomposition of sodium azide as their sources of gas for rapid inflation, represented in the reacti

NeTakaya

Answer : The mass of $NaN_3$ required is 71.175 grams.

Explanation :

To calculate the moles of nitrogen gas, we use the equation given by ideal gas :

PV = nRT

where,

P = Pressure of nitrogen gas = 763 torr

V = Volume of the nitrogen gas = 40.0 L

n = number of moles of gas = ?

R = Gas constant = $62.364\text{ L.torr }mol^{-1}K^{-1}$

T = Temperature of helium gas = $25^oC=273+25=298K$

Putting values in above equation, we get:

$763torr\times 40.0L=n\times 62.364\text{ L.torr }mol^{-1}K^{-1}\times 298K\\\\n=1.642mol$

Now we have to calculate the moles of $NaN_3$ .

The balanced chemical reaction is:

$2NaN_3(s)\rightarrow 2Na(s)+3N_2(g)$

From the balanced chemical reaction, we conclude that

As, 3 moles of $N_2$ produced from 2 moles $NaN_3$

So, 1.642 moles of $N_2$ produced from $\frac{2}{3}\times 1.642=1.095$ moles $NaN_3$

Now we have to calculate the mass of $NaN_3$ .

Molar mass of $NaN_3$ = 65 g/mol

$\text{Mass of }NaN_3=\text{Moles of }NaN_3\times \text{Molar mass of }NaN_3$

$\text{Mass of }NaN_3=1.095mole\times 65g/mole=71.175g$

Therefore, the mass of $NaN_3$ required is 71.175 grams.

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4 years ago

A Canadian driving from Quebec to Montreal finds he has traveled 271 km. How many miles is this? There are 1.61 km in 1 mi

kotegsom [21]

Answer:

168.32 mile

Explanation:

1 mile = 1.61 km

1.61 km = 1 mile

1 km = 1 / 1.61 mile

So, 271 km = 271 / 1.61 = 168.32 mile

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3 years ago

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Vsevolod [243]

Metamorphosis that's all I know

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4 years ago

an airplane releases a ball as it flies parallel to the ground at a height of 235m. if the ball lands on the ground exactly at 2

Oksanka [162]

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3 years ago