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2 years ago

Chemistry Questions: Which of the following is a reasonable ground-state electron configuration?

1 answer:

5 0

A ground state electron configuration follows the Aufbau Principle that states that electrons should be filled up in orbitals in increasing energy. In the given sequences, the right configuration is
<span>1s2 2s2 2p6 3s2 3p6 4s2 3d8.

2) the possible confirmation that follows Aufbau's principle is
D. </span><span>-[Kr] 5s24d105p3</span>

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Isotope Atomic Mass (amu) Percent Abundance

exis [7]

Answer:

The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.

Explanation:

Given data:

Atomic mass of silicon= ?

Percent abundance of Si-28 = 92.21%

Atomic mass of Si-28 = 27.98 amu

Percent abundance of Si-29 = 4.70%

Atomic mass of Si-29 = 28.98 amu

Percent abundance of Si-30 = 3.09%

Atomic mass of Si-30 = 29.97 amu

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+(abundance of 2nd isotope × its atomic mass) / 100

Average atomic mass = (92.21×27.98)+(4.70×28.98)+(3.09×29.97) /100

Average atomic mass = 2580.04 +136.21+92.61 / 100

Average atomic mass = 2808.86 / 100

Average atomic mass = 28.08amu.

The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.

7 0

2 years ago

Read 2 more answers

Convert the following temperature to c 67k b) 1671k

kap26 [50]

Convert Kelvin to °c

(a) 67°c

Formula:-

k=°c+273

°c = 273 - k

°c = 273-67= 206 °c

(b) 1671 k

k=°c+273

°c = 273 - k

°c= 273-1671 = -1398°c

8 0

2 years ago

Radioactive cobalt-60 is frequently used in treating cancer. It took 24 years for a 10 gram sample to decay to 0.625 grams. What

-BARSIC- [3]

Answer:

Half life is 6 years.

Explanation:

T½ = In2 / λ

Where λ = decay constant.

But N = No * e^-λt

Where N = final mass after a certain period of time

No = initial mass

T = time

N = 0.625g

No = 10g

t = 24 years

N = No* e^-λt

N / No = e^-λt

λ = -( 1 / t) In N / No (inverse of e is In. Check logarithmic rules)

λ = -(1 / 24) * In (0.625/10)

λ = -0.04167 * In(0.0625)

λ = -0.04167 * (-2.77)

λ = 0.1154

T½ = In2 / λ

T½ = 0.693 / 0.1154

T½ = 6.00 years.

The half life of radioactive cobalt-60 is 6 years

5 0

2 years ago

In one of his experiments, Lavoisier placed 10.0 grams of mercury (II) oxide into a sealed container and heated it. The mercury

inysia [295]

Oxygen gas produced : 0.7 g

<h3>Further explanation</h3>

Given

10.0 grams HgO

9.3 grams Hg

Required

Oxygen gas produced

Solution

Reaction⇒Decomposition

2HgO(s)⇒2Hg(l)+O₂(g)

Conservation of mass applies to a closed system, where the masses before and after the reaction are the same

mass of reactants = mass of products

mass HgO = mass Hg + mass O₂

10 g = 9.3 g + mass O₂

mass O₂ = 0.7 g

4 0

3 years ago

Two moles of an ideal gas are placed in a container whose volume is 2.3 x 10^-3 m3. The absolute pressure of the gas is 6.9 x 10

PtichkaEL [24]

Answer:

$K.E.=1.97\times 10^{-21}\ J$

Explanation:

Given that:-

Pressure = $6.9\times 10^5\ Pa$

The expression for the conversion of pressure in Pascal to pressure in atm is shown below:

P (Pa) = $\frac {1}{101325}$ P (atm)

Given the value of pressure = 43,836 Pa

So,

$6.9\times 10^5\ Pa$ = $\frac{6.9\times 10^5}{101325}$ atm

Pressure = 6.80977 atm

Volume = $2.3\times 10^{-3}\ m^3$ = 2.3 L ( 1 m³ = 1000 L)

n = 2 mol

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

6.80977 atm × 2.3 L = 2 mol × 0.0821 L.atm/K.mol × T

⇒T = 95.39 K

The expression for the kinetic energy is:-

$K.E.=\frac{3}{2}\times K\times T$

k is Boltzmann's constant = $1.38\times 10^{-23}\ J/K$

T is the temperature

So, $K.E.=\frac{3}{2}\times 1.38\times 10^{-23}\times 95.39\ J$

$K.E.=1.97\times 10^{-21}\ J$

3 0

2 years ago