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3 years ago

What is the molarity of a solution that contains 4.13g of magnesium bromide in 0.845 L of solution

Chemistry

1 answer:

nevsk [136]3 years ago

4 0

RMM magnesium bromide=184
184g=1 mol
4.13g will have=4.13*1/184=0.022mols
molarity=0.022/0.845=0.027M

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The decomposition of dinitrogen pentoxide, N2O5, to NO2 and O2 is a first-order reaction. At 60°C, the rate constant is 2.8 × 10

Sati [7]

Answer:

a. 113 min

Explanation:

Considering the equilibrium:-

2N₂O₅ ⇔ 4NO₂ + O₂

At t = 0 125 kPa

At t = teq 125 - 2x 4x x

Thus, total pressure = 125 - 2x + 4x + x = 125 - 3x

125 - 3x = 176 kPa

x = 17 kPa

Remaining pressure of N₂O₅ = 125 - 2*17 kPa = 91 kPa

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given that:

The rate constant, k = $2.8\times 10^{-3}$ min⁻¹

Initial concentration $[A_0]$ = 125 kPa

Final concentration $[A_t]$ = 91 kPa

Time = ?

Applying in the above equation, we get that:-

$91=125e^{-2.8\times 10^{-3}\times t}$

$125e^{-2.8\times \:10^{-3}t}=91$

$-2.8\times \:10^{-3}t=\ln \left(\frac{91}{125}\right)$

$t=113\ min$

3 0

2 years ago

How long does it take to electroplate 0.5 mm of gold on an object with a surface area of 31 cm^^ from an Au3+(aq) solution with

konstantin123 [22]

Answer:

It will take 5492 seconds to electroplate 0.5 mm of gold on an object .

Explanation:

Mass of gold = m

Volume of gold = v

Surface area on which gold is plated = $a=31 cm^2$

Thickness of the gold plating = h = 0.5 mm = 0.05 cm

1 mm = 0.1 cm

$V=a\times h=31 cm^2\times 0.05 cm=1.55 cm^3$

Density of the gold = $d=19.3 g/cm^3$

$m=d\times v=19.3 g/cm^3\times 1.55 cm^3=29.915g$

Moles of gold = $\frac{29.915 g}{197 g/mol}=0.152 mol$

$Au^{3+}+3e^-\rightarrow Au$

According to reaction, 1 mole of gold required 3 moles of electrons,then 0.152 moles of gold will require :

$\frac{3}{1}\times 0.152 mol=0.456 mol$ of electrons

Number of electrons = N = $0.456\times \times 6.022\times 10^{23}$

Charge on single electron = $q=1.6\times 10^{-19} C$

Total charge required = Q

$Q=N\times q$

Amount of current passes = I = 8 Ampere

Duration of time = T

$I=\frac{Q}{T}$

$T=\frac{N\times q}{I}$

$=\frac{0.456\times \times 6.022\times 10^{23}\times 1.6\times 10^{-19} C}{8 A}=5492 s$

It will take 5492 seconds to electroplate 0.5 mm of gold on an object .

7 0

2 years ago

How water deposits soil sediment and rock

Oliga [24]

Water deposits soil ,sediments ,and rock by moving them to a different place .Say like a beach .The ocean is currently moving the bits of sand and (glass:sand)rock pieces and always ending up in new places.Same as a river.!!!!

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3 years ago

What is the molecular formula of C,H,O

DIA [1.3K]

Answer:

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...

what is the molecular formula of the compound?

Empirical formula Molar mass (g/mol) Molecular formula

CHO 116.1

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Explanation:

Hope this helps

8 0

3 years ago

1. An atom of an elephant has atomic mass of 39 and has number of neutrons as 20 calculate protons number.

r-ruslan [8.4K]

Answer:

See Explanation

Explanation:

1) Let us recall that;

Mass number = number of protons + number of neutrons

Where;

Number of protons = ?

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Mass number =39

Number of protons = mass number - number of neutrons

Mass of protons =39 - 20= 19 protons

2) Atomic number = 13

Number of neutrons =14

Then the mass number =13 +14 =27

The symbol of the element is 27X13

The number of protons= the number of electrons =13

The atomic number is the same as the proton number =13

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2 years ago