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3 years ago

14

If a sample of air in a school container was heated, would the percentage of oxygen in the air increase, decrease, or remain unc

hanged?

1 answer:

Viktor [21]3 years ago

5 0

Answer:

increase

Explanation:

Let's suppose we have a sample of air in a closed container. We heat the container and we want to predict what would happen to the pressure.

According to Gay-Lussac's law, the pressure of a gas is directly proportional to its absolute temperature.

Thus, if we increased the temperature of the air by heating it, its pressure would increase.

If a sample of air in a closed container was heated, the total pressure of the air would increase.

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What really is the Ebola virus?

Sloan [31]

The Ebola virus belongs to a family of viruses termed Filoviridae. Filovirus particles form long sometimes branched filaments of varying shapes, as well as shorter filaments , and may measure up to 14,000 nanometers in length with diameter of 80 nanometers. Viral particles contain one molecule of single stranded RNA enveloped in a lipid membrane. New viral particle bud from the surface of their host cell. Although Ebola virus was only discovered in 1976, it is an ancient virus and is thought to have split from other viruses thousands of years ago.

7 0

3 years ago

Give the name and formula of the compound formed from the following elements: (a) sodium and nitrogen; (b) oxygen and strontium;

lisov135 [29]

<u>Answer:</u>

<u>For a:</u> The chemical name and chemical formula formed is sodium nitride and $Na_3N$

<u>For b:</u> The chemical name and chemical formula formed is strontium oxide and $SrO$

<u>For c:</u> The chemical name and chemical formula formed is aluminium chloride and $AlCl_3$

<u>Explanation:</u>

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

The nomenclature of ionic compounds is given by:

1. Positive is written first.

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

<u>For a:</u> Sodium and nitrogen:

Sodium is the 11th element of periodic table having electronic configuration of $[Ne]3s^1$

To form $Na^{+}$ ion, this element will loose 1 electron.

Nitrogen is the 7th element of periodic table having electronic configuration of $[He]2s^22p^3$ .

To form $N^{3-}$ ion, this element will gain 3 electrons.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for sodium nitride is $Na_3N$

<u>For b:</u> Oxygen and strontium

Strontium is the 38th element of periodic table having electronic configuration of $[Kr]5s^2$ .

To form $Sr^{2+}$ ion, this element will loose 2 electrons.

Oxygen is the 8th element of periodic table having electronic configuration of $[He]2s^22p^4$ .

To form $O^{2-}$ ion, this element will gain 2 electrons.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for strontium oxide is $SrO$

<u>For c:</u> Aluminium and chlorine

Aluminium is the 13th element of periodic table having electronic configuration of $[Ne]3s^23p^1$

To form $Al^{3+}$ ion, this element will loose 3 electrons.

Chlorine is the 17th element of the periodic table having electronic configuration of $[Ne]3s^23p^5$

To form $Cl^{-}$ ion, this element will gain 1 electron.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for aluminium chloride is $AlCl_3$

4 0

4 years ago

At a certain temperature the vapor pressure of pure thiophene is measured to be . Suppose a solution is prepared by mixing of th

Lesechka [4]

Answer:

0.35 atm

Explanation:

It seems the question is incomplete. But an internet search shows me these values for the question:

" At a certain temperature the vapor pressure of pure thiophene (C₄H₄S) is measured to be 0.60 atm. Suppose a solution is prepared by mixing 137. g of thiophene and 111. g of heptane (C₇H₁₆). Calculate the partial pressure of thiophene vapor above this solution. Be sure your answer has the correct number of significant digits. Note for advanced students: you may assume the solution is ideal."

Keep in mind that if the values in your question are different, your answer will be different too. <em>However the methodology will remain the same.</em>

First we <u>calculate the moles of thiophene and heptane</u>, using their molar mass:

137 g thiophene ÷ 84.14 g/mol = 1.63 moles thiophene

111 g heptane ÷ 100 g/mol = 1.11 moles heptane

Total number of moles = 1.63 + 1.11 = 2.74 moles

The<u> mole fraction of thiophene</u> is:

1.63 / 2.74 = 0.59

Finally, the <u>partial pressure of thiophene vapor is</u>:

Partial pressure = Mole Fraction * Vapor pressure of Pure Thiophene

Partial Pressure = 0.59 * 0.60 atm

Pp = 0.35 atm

3 0

3 years ago

Products: 1-methylcyclohexene, 3-methylcyclohexene, methylenecyclohexane

Lostsunrise [7]

Answer:

See explanation

Explanation:

The reaction that we are considering here is quite a knotty reaction. It is difficult to decide if the mechanism is actually E1 or E2 since both are equally probable based on the mass of scientific evidence regarding this reaction. However, we can easily assume that the methylenecyclohexane was formed by an E1 mechanism.

Looking at the products, one could convincingly assert that the reaction leading to the formation of the two main products proceeds via an E1 mechanism with the formation of a carbocation intermediate as has been shown in mechanism attached to this answer. Possible rearrangement of the carbocation yields the 3-methylcyclohexene product.

8 0

3 years ago

A 10 gram sample of iron reacts with oxygen to form 18.2 grams of ferric oxide. How many grams of oxygen reacted?

RoseWind [281]

Answer:

$\boxed {\boxed {\sf 8.2 \ grams}}$

Explanation:

According to the Law of Conservation of Mass, the mass of the products must equal the mass of the reactants.

mass products = mass reactants

In this problem, the reaction is:

$iron + oxygen = ferric \ oxygen$

The reactants are iron and oxygen. We know the mass of the iron sample is 10 grams.

The product is ferric oxide. The mass of the ferric oxide sample is 18.2 grams.

$10 \ g + oxygen=18.2 \ g$

We want to find how many grams of oxygen reacted. We have to get the oxygen by itself. 10 is being added to oxygen. The inverse of addition is subtraction. Subtract 10 from both sides of the equation.

$10 \ g - 10 \ g+ oxygen = 18.2 \ g - 10 \ g$

$oxygen= 18.2 \ g - 10 \ g$

$oxygen= 8.2 \ g \\$

<u>8.2 grams of oxygen </u>reacted with 10 grams of iron to form 18.2 grams of ferric oxide.

8 0

3 years ago