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3 years ago

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A 0.495 g sample of iron containing salt required 20.22 mL of 0.0194 M permanganate solution to reach the endpointof a titration

. What is the percent of iron (55.845 g/mol) in the salt

1 answer:

kogti [31]3 years ago

6 0

Answer:

% Fe in the sample = 22.0%

Explanation:

The redox reaction between iron and permanganate is:

$MnO_{4}^{-}+5Fe^{2+}+8H^{+}\rightarrow Mn^{2+}+5Fe^{3+}+4H2O$

Moles of permanganate required is:

$molarity*volume = 0.0194 mols/L*0.02022L = 0.000392\ moles$

Based on the reaction stoichiometry:

5 moles of iron requires 1 mole of permanganate solution

Therefore, 0.000392 mols of permanganate would need:

$=\frac{0.000392\ mols\ permanganate*5\ mols\ iron}{1\ mol\ permanganate} =0.00196\ mols$

Mol mass of iron (Fe) = 55.845 g/mol

Mass of iron present is:

$=moles*mol.mass = 0.00196mols*55.845g/mol=0.109 g$ $Percent\ iron = \frac{Mass(iron)}{Mass(sample)} *100\\\\Percent\ iron =\frac{0.109}{0.495} *100=22.0$

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question 11 use the internet to look up the sds for 2.0 m sodium hydroxide, naoh, to answer the following questions: a) list the

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The compound is basic in nature but the concentration substance is corrosive.

<h3>What is NaOH?</h3>

Sodium hydroxide is a compound that is formed from sodium and hydrogen as well as oxygen The compound is basic in nature but the concentration substance is corrosive.

a) The acute health effect of exposure to NaOH is skin burn while the chronic effect of exposure is damage to the lungs.

b) The first aid for the ingestion of NaOH is to take in plenty of water.

c) The compound is not flammable

d) The chemicals that could produce a dangerous reaction with NaOH are acids

e) To handle small spills, irrigate the affected area with plenty water and use lab coats, gloves and eye wear when working with the solution.

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1 year ago

Classify each of the following as a homogeneous or heterogeneous substance.

Mnenie [13.5K]

Answer:

a). iron ore - is a heterogeneous substance.

b). quartz - is a homogeneous substance.

c). granite - is a heterogeneous substance.

d). energy drink - is a heterogeneous substance.

e). oil-and-vinegar salad dressing - is a heterogeneous substance.

f). salt - is a homogeneous substance.

g). rainwater - is a heterogeneous substance.

h). nitrogen - is a homogeneous substance.

Explanation:

a). iron ore - is a heterogeneous substance as iron core contains iron and other impurities

b). quartz - is a homogeneous substance as it is only made up of carbon

c). granite - is a heterogeneous substance as it is made up of multiple minerals.

d). energy drink - is a heterogeneous substance as it contains various substances mixed in it

e). oil-and-vinegar salad dressing - is a heterogeneous substance as oil and vinegar itself are different compounds

f). salt - is a homogeneous substance as it only contains one type of molecule

g). rainwater - is a heterogeneous substance as it contains water and other minerals

h). nitrogen - is a homogeneous substance as it is only made of one type of molecule.

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1 year ago

Excess magnesium reacts with 165.0 grams of hydrochloric acid in a single displacement reaction.

JulsSmile [24]

Answer:

The volume of hydrogen gas produced will be approximately 50.7 liters under STP.

Explanation:

Relative atomic mass data from a modern periodic table:

H: 1.008;
Cl: 35.45.

Magnesium is a reactive metal. It reacts with hydrochloric acid to produce

Hydrogen gas $\rm H_2$ , and
Magnesium chloride, which is a salt.

The chemical equation will be something like

$\rm ?\;Mg\;(s) + ?\;HCl \;(aq)\to ?\;H_2 \;(g)+ [\text{Formula of the Salt}]$ ,

where the coefficients and the formula of the salt are to be found.

To determine the number of moles of $\rm H_2$ that will be produced, first find the formula of the salt, magnesium chloride.

Magnesium is a group 2 metal. The oxidation state of magnesium in compounds tends to be +2.

On the other hand, the charge on each chloride ion is -1. Each magnesium ion needs to pair up with two chloride ions for the charge to balance in the salt, magnesium chloride. The formula for the salt will be $\rm MgCl_2$ .

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ ?\;MgCl_2\;(aq)$ .

Balance the equation. $\rm MgCl_2$ contains the largest number of atoms among all species in this reaction. Start by setting its coefficient to 1.

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ {\bf 1\;MgCl_2}\;(aq)$ .

The number of $\rm Mg$ and $\rm Cl$ atoms shall be the same on both sides. Therefore

$\rm {\bf 1\;Mg}\;(s) + {\bf 2\;HCl}\;(aq) \to ?\;H_2 \;(g)+ {1\;\underset{\wedge}{Mg}\underset{\wedge}{Cl_2}}\;(aq)$ .

The number of $\rm H$ atoms shall also conserve. Hence the equation:

$\rm {1\;Mg}\;(s) + {2\;\underset{\wedge}{H}Cl}\;(aq) \to {\bf 1\;H_2 \;(g)}+ {1\;MgCl_2}\;(aq)$ .

How many moles of HCl are available?

$M(\rm HCl) = 1.008 + 35.45 = 36.458\;g\cdot mol^{-1}$ .

$\displaystyle n({\rm HCl}) = \frac{m(\text{HCl})}{M(\text{HCl})} = \rm \frac{165.0\;g}{36.458\;g\cdot mol^{-1}} = 4.52576\;mol$ .

How many moles of Hydrogen gas will be produced?

Refer to the balanced chemical equation, the coefficient in front of $\rm HCl$ is 2 while the coefficient in front of $\rm H_2$ is 1. In other words, it will take two moles of $\rm HCl$ to produce one mole of $\rm H_2$ . $\rm 4.52576\;mol$ of $\rm HCl$ will produce only one half as much $\rm H_2$ .

Alternatively, consider the ratio between the coefficient in front of $\rm H_2$ and $\rm HCl$ is:

$\displaystyle \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}$ .

$\displaystyle n(\text{H}_2) = n(\text{HCl})\cdot \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}\;n(\text{HCl}) = \rm \frac{1}{2}\times 4.52576\;mol = 2.26288\;mol$ .

What will be the volume of that many hydrogen gas?

One mole of an ideal gas occupies a volume of 22.4 liters under STP (where the pressure is 1 atm.) On certain textbook where STP is defined as $\rm 1.00\times 10^{5}\;Pa$ , that volume will be 22.7 liters.

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.4\;L\cdot mol^{-1} = 50.69\; L$ , or

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.7\;L\cdot mol^{-1} = 51.37\; L$ .

The value "165.0 grams" from the question comes with four significant figures. Keep more significant figures than that in calculations. Round the final result to four significant figures.

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3 years ago

Consider the reaction below. HI + H2O mc014-1.jpg H3O+ + I– Which is an acid-conjugate base pair? HI and H2O H2O and H3O+ H3O+ a

lesya692 [45]

Answer: Option (d) is the correct answer.

Explanation:

According to Bronsted-Lowry, species which donate a proton are known as acid. The species which accept a proton are known as a base.

In the given reaction, acids and bases are as follows.

HI + $H_{2}O$ $\rightarrow$ $H_{3}O^{+}$ + $I^{-}$

Acid Base Conjugate acid Conjugate base

Therefore, the acid HI loses a proton to form a conjugate base that is $I^{-}$ .

Thus, we can conclude that HI and $I^{-}$ is an acid conjugate base pair.

4 0

3 years ago

Read 2 more answers

Consider the reaction between iron (III) oxide, Fe2O3 and carbon monoxide, CO. Fe2O3 + 3CO --> 2Fe + 3CO2 In the process, 213

s344n2d4d5 [400]

To calculate the mass of Fe formed in a) we get first the limiting reactant between Fe2O3 and CO. Given the masses, the ratio of Fe2O3 is 1.33 while that of CO is 1.67. Hence the limiting reagent is Fe2O3. The mass of Fe formed is 148.98 grams. In b, the needed CO is only 112.04 grams. Hence, the excess is 27. 96 grams.

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3 years ago