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soldi70 [24.7K]
3 years ago
14

The amount of lead in drinking water is 0.025 mg/L. Express this concentration in molality. {molar mass of lead is 207.2 g/mol a

nd the density of water is 1.00 g/cm.}
Chemistry
1 answer:
Andru [333]3 years ago
8 0
0.025 mg = 25E-3 g Pb. 
<span>mols Pb = grams Pb/atomic mass Pb. </span>

<span>1000 mL H2O x 1.00 g/mL = 1000 g = 1 kg. </span>
<span>molality = mols Pb/kg H2O

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions here.
</span>
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If 5.4 moles of Fe react with 4.7 moles of O2, what is the maximum amount of Fe2O3 (in moles) that can be produced? What is the
DIA [1.3K]

Answer:

2.7 moles of Fe₂O₃ is the maximum amount that can be produced. Iron is the limiting reactant.

Explanation:

The balanced reaction is:

4 Fe + 3 O₂ → 2 Fe₂O₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:

  • Fe: 4 moles
  • O₂: 3 moles
  • Fe₂O3: 2 moles

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

You can use a simple rule of three as follows: if by stoichiometry 4 moles of Fe reacts with 3 moles of O₂, how much moles of Fe will be needed if 4.7 moles of O₂ react?

moles of Fe =\frac{4. moles of Fe*4.7 moles of O_{2}}{3 moles of O_{2} }

moles of O₂= 6.27

But 6.27 moles of Fe are not available, 5.4 moles are available. Since you have less moles than you need to react with 4.7 moles of O₂, iron Fe will be the limiting reagent.

So you can use a simple rule of three as follows: if by stoichiometry 4 moles of Fe produce 2 moles of Fe₂O₃, how many moles of Fe₂O₃ will be produced if 5.4 moles of Fe react?

moles of Fe_{2}O_{3}=\frac{5.4 moles of Fe*2 moles of Fe_{2} O_{3} }{4 moles of Fe}

moles of Fe₂O₃= 2.7 moles

Then:

<u><em>2.7 moles of Fe₂O₃ is the maximum amount that can be produced. Iron is the limiting reactant.</em></u>

4 0
3 years ago
what is the mole fraction of ethanol c2h5oh in an aqueous solution that is 46 perccent ethanol by mass?
kari74 [83]

The mole fraction of ethanol c2h5oh in an aqueous solution that is 46 percent ethanol by mass is 0.25

Mole fraction is the mole of one of the component of the solution divided by the total moles of the solution

Calculating the mole fraction of ethanol,we get

Percentage by weight of ethyl alcohol is 46% which implies in 100 g of this solution is 46 g while the mass of the water will be 54% of 100 g = 54g.

Finding the moles of water and the ethyl alcohol {molar mass of water(H₂O) = 18 and molar mass of ethyl alcohol(C₂H₆O = 46}

Moles = mass/molar mass

moles of ethanol = 46/46 = 1

moles of water = 54/18 = 3

ntotal=1+3=4

Mole fraction of ethanol is:

  Mole of ethanol            =   1/4

   Total mole of solution

Hence, the mole fraction is 1/4 or 0.25

To learn more about mole fraction visit:

brainly.com/question/8076655

#SPJ4

7 0
2 years ago
If you start with 89.3 g no(g) and 28.6 g h2(g), find the theoretical yield of ammonia.
Tatiana [17]
Balanced equation: 
<span>2 NO + 5 H2 ------> 2 NH3 + 2 H2O
 </span>
<span>2 moles NO react with 5 moles H2 to produce 2 moles NH3
 </span>
<span>Molar mass of NO = 30.00 g/mol </span>
<span>86.3g NO = 86.3/30.00 = 2.877 moles of NO </span>

<span>This will require: 2.877*5 / 2 = 7.192 moles of H2 </span>

<span>Molar mass of H2 = 2 g/mol </span>
<span>25.6g H2 = 25.6/2 = 12.7 mol H2. </span>
<span>You have excess H2 means the NO is limiting </span>

<span>From the balanced equation: </span>
<span>2 moles of NO will produce 2 moles of NH3 </span>
<span>2.877 moles of NO will produce 2.877 moles of NH3 </span>

<span>Molar mass NH3 = 17g/mol </span>
<span>Mass NH3 produced = 2.877 * 17 = 48.91g 

Hence the yield is = 48.91 g ~ 49 g</span>
3 0
3 years ago
Read 2 more answers
The densities of crystalline co2 and nh3 at 160 k are 1.56 and 0.84 g/cm3, respectively. calculate their molar volumes.
Neporo4naja [7]
The molar volume, symbol Vm<span>, is the </span>volume occupied by one mole of a substance at a given temperature and pressure. <span>It is equal to the </span>molar<span> mass divided by the mass density. Therefore, we calculate as follows:

Vm(CO2) = 44.01 / 1.56 = 28.21 cm^3 / mol
</span>Vm(NH3) = 17.03 / 0.84 = 20.27 cm^3 / mol
7 0
3 years ago
Read 2 more answers
Balance the following:<br> CsH12 +<br> 02<br> CO2+<br> |<br> H20
user100 [1]

Answer:

C5H12+8O2-->5CO2+6H20

7 0
3 years ago
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