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Zina [86]
3 years ago
6

How many naturally occurring elements are there

Chemistry
1 answer:
arlik [135]3 years ago
4 0

Answer: Out of 118 elements, 94 occur naturally

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A container has a mixture of NO2 gas and N2O4 gas in equilibrium. The chemical reaction between the two gases is described by th
kondaur [170]

Answer: The most likely partial pressures are 98.7MPa for NO₂ and 101.3MPa for N₂O₄

Explanation: To determine the partial pressures of each gas after the increase of pressure, it can be used the equilibrium constant Kp.

For the reaction 2NO₂ ⇄ N₂O₄, the equilibrium constant is:

Kp = \frac{P(N_{2}O_{4} )}{P(NO_{2} ^{2}) }

where:

P(N₂O₄) and P(NO₂) are the partial pressure of each gas.

Calculating constant:

Kp = \frac{38.8}{61.2^{2} }

Kp = 0.0104

After the weights, the total pressure increase to 200 MPa. However, at equilibrium, the constant is the same.

P(N₂O₄) + P(NO₂) = 200

P(N₂O₄) = 200 - P(NO₂)

Kp = \frac{P(N_{2}O_{4} )}{P(NO_{2} ^{2}) }

0.0104 = \frac{200 - P(NO_{2})  }{[P(NO_{2} )]^{2}}

0.0104[P(NO_{2} )]^{2} + P(NO_{2} ) - 200 = 0

Resolving the second degree equation:

P(NO_{2} ) = \frac{-1+\sqrt{9.32} }{0.0208}

P(NO_{2} ) = 98.7

Find partial pressure of N₂O₄:

P(N₂O₄) = 200 - P(NO₂)

P(N₂O₄) = 200 - 98.7

P(N₂O₄) = 101.3

The partial pressures are P(NO_{2} ) = 98.7 MPa and P(N₂O₄) = 101.3 MPa

3 0
3 years ago
Which process is an oxidation?
Zarrin [17]
<span>The problem has to do with oxidation states of the matter. The oxidation state of oxygen will always be -2 with the exception of peroxides which will have a state of -1. The overall balanced state of chemical compounds will be 0, so the oxidation state of Mn in MnO2 will be +4. The oxidation state of MnO4- will then be +7 to balance out to the negative one charge. The state change from +4 to +7 is 3, thus three electrons have to be lost in order for this to happen; a loss of a charge of -3 results in an increase of charge of 3. Oxidation is always the process of 'losing' electrons.

</span><span>E] MnO2(s) MnO4-(aq</span>
4 0
3 years ago
The density of Mg is 1.74g/cm3. The density of strontium is 2.60g/cm3. What would you expect the density of Ca to be?
Tomtit [17]

The density of Ca will be between that of Mg and Sr

Explanation:

Ca, Mg and Sr are group II elements. They are called alkali earth metals. The correct order of the elements in this group are: Be, Mg, Ca, Sr, Ba and Ra.

Density is an intensive property of matter which describes the amount of matter(mass) per volume of a substance.

  • Density varies proportionally with mass. The higher the mass, the higher its density.
  • On the periodic table, atomic mass which the number of protons and neutrons in the nucleus of an atom increases down the group.
  • This implies a progradation in the value of density down the group. Therefore one expects that the value of density of Ca will fall between that of Mg and Sr. It cannot be more than 2.6g/cm³ nor less than 1.74g/cm³.

Learn more:

density brainly.com/question/2658982

mass number brainly.com/question/2597088

#learnwithBrainly

                   

6 0
3 years ago
Question about thermodynamics
Fiesta28 [93]

Answer:

Thermodynamics is the branch of physics that deals with the relationships between heat and other forms of energy.

4 0
3 years ago
Bob adds heat to a substance. When enough heat is added, A. its particles move closer together and the substance becomes a gas.
Elena L [17]

Answer:

C. its particles move farther apart and the substance becomes a gas.

Explanation:

A. is wrong because moving closer together creates a solid, not a gas.

B. is wrong because moving father apart creates a gas, not solid.

C. is correct because moving farther apart creates a gas.

D. is wrong because when heat is added particles spread apart because they vibrate faster. Although, in a solid the particles are closer together.

- Just know the states of matter and how the particles move and that will help with this problem.

6 0
3 years ago
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