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3 years ago

Baking soda (nahco3) is an active ingredient in some antacids. determine the percent composition of oxygen in baking soda.

1 answer:

8 0

Assuming the question is asking for percent composition by mass,

The molar mass of sodium bicarbonate is:

22.990 + 1.008 + 12.011 + 3*15.999 = 84.006 g/mol

The molar mass of 3 oxygen atoms is:

3*15.999 = 47.997 g/mol

The percentage composition by mass is:

47.997/84.006 * 100% = 57.1% (3 s.f.)

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Which statement describes J.J. Thomson’s plum-pudding model of the atom?

ra1l [238]

Option C: the electrons are embedded in a positive sphere.

As we know that was a wrong model and nowadays the electrons are considered to be around the nucleus, in regions called orbitals.

4 0

4 years ago

How many molecules of CO2 are present

allochka39001 [22]

Where’s the question or equation

6 0

3 years ago

Oxygen gas can be prepared by heating potassium chlorate according to the following equation:2KClO3(s)Arrow.gif2KCl(s) + 3O2(g)T

Eduardwww [97]

Answer:

Moles of potassium chlorate reacted = 0.2529 moles

The amount of oxygen gas collected will be 12.8675 g

Explanation:

(a)

We are given:

Vapor pressure of water = 17.5 mmHg

Total vapor pressure = 748 mmHg

Vapor pressure of Oxygen gas = Total vapor pressure - Vapor pressure of water = (748 - 17.5) mmHg = 730.5 mmHg

To calculate the amount of Oxygen gas collected, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 730.5 mmHg

V = Volume of the gas = 9.49 L

T = Temperature of the gas = $20^oC=[20+273]K=293K$

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

n = number of moles of oxygen gas = ?

Putting values in above equation, we get:

$730.5mmHg\times 9.49L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 293K\\\\n=\frac{730.5\times 9.49}{62.3637\times 293}=0.3794mol$

According to the reaction shown below as:-

$2KClO_3(s)\rightarrow 2KCl(s) +3O_2(g)$

3 moles of oxygen gas are produced when 2 moles of potassium chlorate undergoes reaction.

So,

0.3794 mol of oxygen gas are produced when $\frac{2}{3}\times 0.3794$ moles of potassium chlorate undergoes reaction.

<u>Moles of potassium chlorate reacted = 0.2529 moles</u>

(b)

We are given:

Vapor pressure of water = 17.5 mmHg

Total vapor pressure = 753 mmHg

Vapor pressure of Oxygen gas = Total vapor pressure - Vapor pressure of water = (753 - 17.5) mmHg = 735.5 mmHg

To calculate the amount of Oxygen gas collected, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 735.5 mmHg

V = Volume of the gas = 9.99 L

T = Temperature of the gas = $20^oC=[20+273]K=293K$

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

n = number of moles of oxygen gas = ?

Putting values in above equation, we get:

$735.5mmHg\times 9.99L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 293K\\\\n=\frac{735.5\times 9.99}{62.3637\times 293}=0.40211mol$

Moles of Oxygen gas = 0.40211 moles

Molar mass of Oxygen gas = 32 g/mol

Putting values in above equation, we get:

$0.037mol=\frac{\text{Mass of Oxygen gas}}{2g/mol}\\\\\text{Mass of Oxygen gas}=(0.40211mol\times 32g/mol)=12.8675g$

<u>Hence, the amount of oxygen gas collected will be 12.8675 g</u>

5 0

3 years ago

Show all calculations. 1. 2 C 4 H 10 + 13 O 2 -> 8 CO 2 + 10 H 2 O a) what mass of O 2 will react with 400 g C 4 H 10? b) how

bazaltina [42]

$\\ \tt\hookrightarrow 2C_4H_10+13O_2\longrightarrow 8CO_2+10H_2O$

13mol of O_2 reacts with 2mols of C_4H_10.
7.5mol of O_2 reacts with 1mol of C_4H_10

No of moles:-

$\\ \tt\hookrightarrow \dfrac{Given\:mass}{Molar\:mass}$

$\\ \tt\hookrightarrow \dfrac{400}{58}$

$\\ \tt\hookrightarrow 6.89mol$

Now

Moles of O_2

$\\ \tt\hookrightarrow 7.5(6.89)=51.6mol$

Mass of O_2

$\\ \tt\hookrightarrow 51.6(32)=1651.2g$

4 0

2 years ago

Adding energy has no effect on the rate of evaporation? True or False ?

zlopas [31]

Answer:

False

Explanation:

Evaporation occurs when molecules in a liquid gain enough energy that they overcome attractions from other molecules and break away to become a gas. Adding energy increases the rate of evaporation.

Hope this helped!

5 0

3 years ago