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3 years ago

The 64.8-g sample of the compound X2O5 contains 48.0 g of oxygen atoms. What is the molar mass of element X?

1 answer:

8 0

The answer is 14 g/mol.

The number of moles (n) is the ratio of mass (m) and molar mass (M):
n = m : M

Step 1. Calculate number of moles of oxygen in the compound.
n = ?
m = 48 g
M = 16 g/mol

n = m/M = 48 g : 16 g/mol = 3 mol

Step 2. Calculate the number of moles of the element X:
5 atoms of oxygen is 3 mol.
2 atoms of element X is x
5 : 3 = 2 :x
x = 2 * 3 / 5 = 6/5 = 1.2 mol

Step 3. Calculate the molar mass of element X
n = 1.2 mol
m = 64.8 g - 48 g = 16.8 g
M = ?

n = m : M
M = m : n
M = 16.8 g : 1.2 mol = 14 g/mol

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For the reaction Fe3O4(s) + 4H2(g) --> 3Fe(s) + 4H2O(g)

mojhsa [17]

Answer : The value of equilibrium constant for this reaction at 328.0 K is $1.70\times 10^{15}$

Explanation :

As we know that,

$\Delta G^o=\Delta H^o-T\Delta S^o$

where,

$\Delta G^o$ = standard Gibbs free energy = ?

$\Delta H^o$ = standard enthalpy = 151.2 kJ = 151200 J

$\Delta S^o$ = standard entropy = 169.4 J/K

T = temperature of reaction = 328.0 K

Now put all the given values in the above formula, we get:

$\Delta G^o=(151200J)-(328.0K\times 169.4J/K)$

$\Delta G^o=95636.8J=95.6kJ$

The relation between the equilibrium constant and standard Gibbs free energy is:

$\Delta G^o=-RT\times \ln k$

where,

$\Delta G^o$ = standard Gibbs free energy = 95636.8 J

R = gas constant = 8.314 J/K.mol

T = temperature = 328.0 K

K = equilibrium constant = ?

Now put all the given values in the above formula, we get:

$95636.8J=-(8.314J/K.mol)\times (328.0K)\times \ln k$

$k=1.70\times 10^{15}$

Therefore, the value of equilibrium constant for this reaction at 328.0 K is $1.70\times 10^{15}$

3 0

3 years ago

Which discovery did J. J. Thomson make that improved upon Dalton's atomic theory?

erik [133]

Answer: Atoms contain tiny, negatively charged electrons

Explanation: Thomson's experiments with cathode ray tubes helped him to discover the electron (which Dalton did not know about). Dalton thought that atoms were indivisible particles, and Thomson's discovery of the electron proved the existence of subatomic particles.

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3 years ago

Why do we say the particles in a rock lying on the ground have kinetic energy and potential energy?

oksano4ka [1.4K]

Answer:

the particles of the rock possess kinetic energy as they stay in a place the particles also contain potential energy due to their position and arrangement This form of stored energy is responsible for keeping the particles together

Explanation:

hop it helps

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3 years ago

slader Consider the following reactions: A. uranium-238 emits an alpha particle; B. plutonium-239 emits an alpha parti- cle; C.

pishuonlain [190]

Answer:

For A: The equation is $_{92}^{238}\textrm{U}\rightarrow _{90}^{234}\textrm{Th}+_2^4\alpha$

For B: The equation is $_{94}^{239}\textrm{Pu}\rightarrow _{92}^{235}\textrm{U}+_2^4\alpha$

For C: The equation is $_{90}^{239}\textrm{Th}\rightarrow _{91}^{235}\textrm{Pa}+_{-1}^0\beta$

Explanation:

Alpha decay process is the process in which nucleus of an atom disintegrates into two particles. The first one which is the alpha particle consists of two protons and two neutrons. This is also known as helium nucleus. The second particle is the daughter nuclei which is the original nucleus minus the alpha particle released.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha$

Beta decay process is defined as the process the neutrons get converted into an electron and a proton. The released electron is known as the beta particle. In this process, the atomic number of the daughter nuclei gets increased by a factor of 1 but the mass number remains the same.

$_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta$

For A: Uranium-238 emits an alpha particle

The nuclear equation for this process follows:

$_{92}^{238}\textrm{U}\rightarrow _{90}^{234}\textrm{Th}+_2^4\alpha$

For B: Plutonium-239 emits an alpha particle

The nuclear equation for this process follows:

$_{94}^{239}\textrm{Pu}\rightarrow _{92}^{235}\textrm{U}+_2^4\alpha$

For C: Thorium-239 emits a beta particle

The nuclear equation for this process follows:

$_{90}^{239}\textrm{Th}\rightarrow _{91}^{235}\textrm{Pa}+_{-1}^0\beta$

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3 years ago

What does resonance result in?

Tcecarenko [31]

louder sounds

Explanation:

Resonance results in louder sounds.

Resonance is a phenomenon that produces a large vibration as a result of smaller vibration that causes the resonating body to vibrate at its own natural frequency.

Resonance results in sound amplification and causes louder sounds. Increasing vibration results in the production of a louder sound.

Learn more:

Resonance in chemistry brainly.com/question/9422880

#learnwithBrainly

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3 years ago