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2 years ago

A 5.00 gram sample of an oxide of lead PbxOy contains 4.33g of lead. Determine the simplest formula for the compound.

1 answer:

8 0

PbO2

You have to take the mass of lead in the problem, and divide by the molar mass.
When you do the same with oxygen, you get a number about twice as large as when you divide the mass of lead by the molar mass of lead. This means that the simplest formula would be PbO2

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In this experiment, 0.170 g of caffeine is dissolved in 10.0 ml of water. the caffeine is extracted from the aqueous solution th

zmey [24]

solution:

Weight of caffeine is W = 0.170 gm.

Volume of water is V= 10 ml

Volume of methylene chloride which extracted caffeine is v= 5ml

No of portions n=3

Distribution co-efficient= 4.6

Total amount of caffeine that can be unextracted is given by

$w_{n}=w\times[\frac{k_{Dx}v}{k_{Dx}v+v}]^n\\w_{3}=0.170[\frac{4.6\times10}{(4.6\times10+5)}]^3\\=0.170[\frac{46}{46+5}]^3\\=0.170[\frac{46}{51}]^3\\=0.170[\frac{97336}{132651}]\\=0.170\times0.734=0.125gms$

amount of caffeine un extracted is 0.125gms

amount of caffeine extracted=0.170-0.125

=0.045 gms

6 0

2 years ago

Write a net ionic equation to show how piperidine, c5h11n, behaves as a base in water.

lidiya [134]

$C_5H_{11}N + H2O ---\ \textgreater \ C_5H_{11}NH^{+} + OH^{-}$

Nitrogen lone pair will act as a base,removing H+ from water leaving behind OH- ion.
Why ?
Because N is a better donor than O.

7 0

2 years ago

An old sample of concentrated sulfuric acid to be used in the laboratory is approximately 98.1 percent h2so4 by mass. calculate

Airida [17]

Basis: 100 mL solution

From the given density, we calculate for the mass of the solution.

density = mass / volume
mass = density x volume

mass = (1.83 g/mL) x (100 mL) = 183 grams

Then, we calculate for the mass H2SO4 given the percentage.

mass of H2SO4 = (183 grams) x (0.981) = 179.523 grams

Calculate for the number of moles of H2SO4,
moles H2SO4 = (179.523 grams) / (98.079 g/mol)
moles H2SO4 = 1.83 moles

Molarity:
M = moles H2SO4 / volume solution (in L)
= 1.83 moles / (0.1L ) = 18.3 M

Molality:
m = moles of H2SO4 / kg of solvent
= 1.83 moles / (183 g)(1-0.983)(1 kg/ 1000 g) = 588.24 m

8 0

2 years ago

What is the empirical formula? A compound is used to treat iron deficiency in people. It contains 36.76% iron, 21.11% sulfur, an

Mandarinka [93]

Answer: The empirical formula of the compound is $Fe_1S_1O_4$

Explanation:

Empirical formula is defined formula which is simplest integer ratio of number of atoms of different elements present in the compound.

Percentage of iron in a compound = 36.76 %

Percentage of sulfur in a compound = 21.11 %

Percentage of oxygen in a compound = 42.13 %

Consider in 100 g of the compound:

Mass of iron in 100 g of compound = 36.76 g

Mass of iron in 100 g of compound = 21.11 g

Mass of iron in 100 g of compound = 42.13 g

Now calculate the number of moles each element:

Moles of iron= $\frac{36.76 g}{55.84 g/mol}=0.658 mol$

Moles of sulfur= $\frac{21.11 g}{32.06 g/mol}=0.658 mol$

Moles of oxygen= $\frac{42.13 g}{16 g/mol}=2.633 mol$

Divide the moles of each element by the smallest number of moles to calculated the ratio of the elements to each other

For Iron element = $\frac{0.658 mol}{0.658 mol}=1$

For sulfur element = $\frac{0.658 mol}{0.658 mol}=1$

For oxygen element = $\frac{2.633 mol}{0.658 mol}=4.001\approx 4$

So, the empirical formula of the compound is $Fe_1S_1O_4$

4 0

1 year ago

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Tanks of compressed gas must be kept away from heat sources. If a compressed–gas tank is heated too much, it may explode and cau

scoundrel [369]

If it is heated while it is being compressed or held inside a container as such, the pressure build up while in the container and the pressure can become so much that the container will burst.

3 0

1 year ago

Read 2 more answers