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4 years ago

Calculate the percentage by mass of lead in pbco3.

Chemistry

2 answers:

Sonja [21]4 years ago

7 0

Answer:

The correct answer is d.

Explanation:

Step 1: First we must obtain the molecular weight of $PbCO_{3}$ and Pb.

$PM_{PbCO_{3} }$ = 267,21 $\frac{g}{mol}$

$PM_{Pb}$ = 207,2 $\frac{g}{mol}$

Step 2: We can now calculate the percentage of lead in a $PbCO_{3}$ molecule by stating a simple rule of three:

$PM_{PbCO_{3} }$ --> 100%.

$PM_{Pb}$ --> X

%Pb = $\frac{PM_{Pb}}{ PM_{PbCO_{3} }} * 100%$

%Pb = $\frac{207.2 \frac{g}{mol}}{267.21 \frac{g}{mol}} * 100%$

%Pb = 77,54 %

Have a nice day!

nignag [31]4 years ago

5 0

Pb/pbco3*100
207/207+12+48
207/267*100
=77.53%

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A mouse is placed in a sealed chamber with air at 769.0 torr. This chamber is equipped with enough solid KOH to absorb any CO2 a

svlad2 [7]

<u>Answer:</u> The amount of oxygen gas consumed by mouse is 0.202 grams.

<u>Explanation:</u>

We are given:

Initial pressure of air = 769.0 torr

Final pressure of air = 717.1 torr

Pressure of oxygen = Pressure decreased = Initial pressure - Final pressure = (769.0 - 717.1) torr = 51.9 torr

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

$PV=nRT$

where,

P = pressure of the gas = 51.9 torr

V = Volume of the gas = 2.20 L

T = Temperature of the gas = 292 K

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

n = number of moles of oxygen gas = ?

Putting values in above equation, we get:

$51.9torr\times 2.20L=n\times 62.364\text{ L. Torr }mol^{-1}K^{-1}\times 292K\\\\n=\frac{51.9\times 2.20}{62.364\times 292}=0.0063mol$

To calculate the mass from given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of oxygen gas = 0.0063 moles

Molar mass of oxygen gas = 32 g/mol

Putting values in above equation, we get:

$0.0063mol=\frac{\text{Mass of oxygen gas}}{32g/mol}\\\\\text{Mass of oxygen gas}=(0.0063mol\times 32g/mol)=0.202g$

Hence, the amount of oxygen gas consumed by mouse is 0.202 grams.

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3 years ago

How do the properties of compounds often compare with the properties of the elements that make them

const2013 [10]

The properties of a compound are nothing like the properties of th elements that combine to make it.

sodium chloride,NaCl, table salt, is a white cubic crystal, stable ionic compound, soluble in water
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chlorine is a yellow green gas that is poisonous and very reactive.

carbon dioxide, CO2, is a clear, colorless gas that puts out fires, plants use but we breath out.
carbon is a black solid, or a diamond
oxygen is a clear colorless gas that is needed for burning and breathing.

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3 years ago

Which is the iupac name for no?

pshichka [43]

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3 years ago

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ValentinkaMS [17]

Answer:

I dont know if this is correct.. but maybe in the tool row, put graduated cylinder because you use graduated cylinders to measure water and for units put milliliters or liters?? Sorry if this isnt correct i wouldnt know what else to put !

Explanation:

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3 years ago

Determine the heat energy needed to raise the temperature of 120 grams of ice at -5 to steam at 115°

CaHeK987 [17]

Answer:

Q = 30355.2 J

Explanation:

Given data:

Mass of ice = 120 g

Initial temperature = -5°C

Final temperature = 115°C

Energy required = ?

Solution:

Specific heat capacity of ice is = 2.108 j/g.°C

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Q = m.c. ΔT

ΔT = T2 -T1

ΔT = 115 - (-5°C)

ΔT = 120 °C

Q = 120 g × 2.108 j/g.°C × 120 °C

Q = 30355.2 J

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4 years ago