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const2013 [10]
3 years ago
15

1. How many grams of chromium metal are plated out when a constant current of 8.00 A is passed through an aqueous solution conta

ining Cr3+ ions for 40.0 minutes?
Chemistry
1 answer:
Paul [167]3 years ago
6 0

ion with charge 3⁺, like Cr³⁺ needs 3 Faradays to plate 1 mole 

Amount of electric charge per mole (faraday's constant) = 96500 C mol¹⁻

Time = 40min = 2400 sec<span>

you have coulombs = amps x sec = 8 x 2400 coulombs </span>

molar mass of Cr = 51.9961g<span>

96500 x 3 coulombs plates 51.9961g Cr 
so 8 x 2400 coulombs gives,</span>

<span>51.9961/(96500 x 3) x 8 x 2400 g Cr = 3.45g Cr </span>

<span>so, 3.45g chromium metal is plated out.</span>

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A physician has ordered 0.50 mg of atropine, intramuscularly. If atropine were available as 0.25 mg/mL of solution, how many mil
sladkih [1.3K]
If 0.25mg of atropine is in 1mL
                  so
    0.50mg of atropine is in x

x=\frac{0.5mg*1mL}{0.25mg}=2mL
6 0
3 years ago
Assuming that an acetic acid solution is 12% by mass and that the density of the solution is 1.00 g/mL, what volume of 1 M NaOH
Doss [256]

Explanation:

Let us assume that total mass of the solution is 100 g. And, as it is given that acetic acid solution is 12% by mass which means that mass of acetic acid is 12 g and 88 g is the water.

Now, calculate the number of moles of acetic acid as its molar mass is 60 g/mol.

    No. of moles = \frac{mass}{\text{molar mass}}

                           = \frac{12 g}{60 g/mol}

                           = 0.2 mol

Molarity of acetic acid is calculated as follows.

              Density = \frac{mass}{volume}

                 1 g/ml = \frac{100 g}{volume}

                    volume = 100 ml

Hence, molarity = \frac{\text{no. of moles}}{volume}

                           = \frac{0.2 mol}{0.1 L}

                           = 2 mol/l

As reaction equation for the given reaction is as follows.

     NaOH + CH_{3}COOH \rightarrow CH_{3}COONa + H_{2}O

So,          moles of NaOH = moles of acetic acid

Let us suppose that moles of NaOH are "x".

          x \times 1 M = 10 mL \times 2 M     (as 1 L = 1000 ml)

                        x = 20 L

Thus, we can conclude that volume of NaOH required is 20 ml.                    

6 0
3 years ago
How many moles of Calcium Oxide are needed to produce 4 moles of Calcium Hydroxide?
Tpy6a [65]

Taking into account the reaction stoichiometry, 2 moles of CaO are required to react with 2 moles of Ca(OH)₂.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

CaO + H₂O → Ca(OH)₂

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

  • CaO: 1 mole
  • H₂O: 1 mole
  • Ca(OH)₂:  1 mole

<h3>Moles of CaO required</h3>

The following rule of three can be applied: If by stoichiometric reaction 1 mole of Ca(OH)₂ is produced by 1 mole of CaO, 2 moles of Ca(OH)₂ are produced by how many moles of CaO?

moles of CaO=\frac{2 moles of Ca(OH)_{2}x1 mol of CaO }{1 mole of Ca(OH)_{2}}

moles of CaO= 2 moles

Finally, 2 moles of CaO are required to react with 2 moles of Ca(OH)₂.

Learn more about the reaction stoichiometry:

brainly.com/question/24741074

brainly.com/question/24653699

#SPJ1

5 0
2 years ago
Why can metals be extracted using carbon
8090 [49]
If a metal is less reactive than carbon, it can be extracted from its oxide by heating with carbon. The carbon displaces the metal from the compound, and removes the oxygen from the oxide. This leaves the metal.
5 0
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A chemistry student needs 60.0 g of tetrahydrofuran for an experiment. By consulting the CRC Handbook of Chemistry and Physics,
Evgen [1.6K]

Answer:

67.492cm^3

Explanation:

To get the volume of tetrahydrofuran needed, what the student need to do is to apply mathematical calculations.

We know quite well that to obtain the volume of a substance, given the mass of the substance and the density of the substance is possible.

The volume of the substance is simply the mass of the substance divided by the density of the substance.

This is thus volume = mass/density

The mass given is the question is 60g while the density given is 0.889g/cm^3

The volume = 60/0.889 = 67.492cm^3

8 0
3 years ago
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