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2 years ago

A filament of a light bulb is made from a pure sample of tungsten.

Chemistry

1 answer:

GenaCL600 [577]2 years ago

8 0

Answer:

The correct options are:

1) Pure chemical substance

2) Element.

Explanation:

each of the term is explained below:

1) Mixture: Since tungsten is an element in periodic table thus it is not a mixture.

2) False by definition of mixture.

3) false by definition of mixture.

4) Solution: Tungsten in a filament is in solid form hence solution is incorrect.

5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.

6) Compound: By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.

7) Tungsten is a element in the periodic table with atomic number 74.

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A gas mixture at 0°C and 1.0atm contains 0.010mol of H2, 0.015mol of O2, and 0.025mol of N2. Assuming ideal behavior, what is th

Olegator [25]

Answer:

PH₂ = 0.2 atm

C) About 0.20atm, because H2 comprises 20% of the total number of moles of gas.

Explanation:

To determine the partial pressure of hydrogen gas (H2) in the mixture,

Partial pressure H₂ = Ptotal * xH₂

xH₂ = Mole fraction of H₂ = ∩H₂ / ( ∩H₂ + ∩O₂ + ∩N₂)

xH₂ = 0.01 / (0.01 + 0.015 + 0.025)

xH₂ = 0.01/0.05

xH₂ = 0.2

therefore

PH₂ = pT * xH₂

PH₂ = 1.0 atm * 0.2

PH₂ = 0.2 atm

so the correct option is C) About 0.20atm, because H2 comprises 20% of the total number of moles of gas.

7 0

2 years ago

When food spoils, it is a chemical reaction. For example, rancid butter is produced when the fat molecules in the butter undergo

Sergio039 [100]

Answer: Decreases the rate of reaction

Remove water from food by dehydration.
Transport food in a refrigerated truck.
Store food in airtight containers.
Store food in a refrigerator after opening.

Does not decrease the rate of reaction

Store food in the open air.
Place food on a warm surface.

Explanation: Dehydration of food excludes water from food which is one of the factor needed by microorganisms for growth, so it decreaese the rate of reaction.

Transporting food in refrigerated trucks lowers the temperature of food and not many microorganisms are active at very low temperatures, so it decreases the rate of reaction.

Storing food in airtight containers excludes air which is one of the factors required for microbial activity, so it decreases reaction rate.

Storing food in refrigerators after opening also lowers the temperature of food and hence the the rate of microbial activity.

Storing food in the open air does not decrease microbial activity instead it provides microorganisms with the favorable conditions for their activity such as air and water from water vapor in the air.

Placing food on a warm surface does not decrease rate of reaction because microorganisms are very active in warm and humid environments.

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1 year ago

Select the statement(s) that explain(s) the relationship between the arrangement of elements by size and first ionization energy

kow [346]

c. A full s subshell is able to shield a newly filled p subshell from the nucleus, making the first electron in a p subshell easy to remove.

Explanation:

From the given options, a full s-sublevel is able to shield a newly filled p-subshell from the nucleus thereby making the first electron in a p-subshell easy to remove is correct.

What is ionization energy?

Ionization energy is a measure of the readiness of an atom to lose an electron.

First ionization energy is the energy required to remove the most loosely held electron in the gas phase.

The size of an atom/element depends on the number of electrons it contains. The more the electrons, the larger its size.

The larger an atom becomes the lesser the ionization energy needed to remove the first electron from its outermost shell.

Electron - electron repulsion occurs when two electrons in the same sub-level repels one another.

Shielding effect is the ability of the inner electrons to protect the outer electrons from the pull of the nuclear charge.

In option C, a s-subshell has a greater shielding effect than the p,d and f sub-shell in that order.

A newly introduced electron in the p-sublevel will be loosely held and easier to remove.

Learn more:

First ionization energy brainly.com/question/2153804

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2 years ago

Read 2 more answers

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PIT_PIT [208]

Answer:

Increasing the volume of the vessel

Explanation:

By the Le Chatelier's principle, if a system in equilibrium suffer a variation that disturbs the equilibriu, the reaction shift in the way to minimize the pertubation and re-establish the equilibrium.

For a variation in pressure, when it increases, the reaction shift for the smallest of gas volume, and if decreases, the reaction will shift for the large gas volume. So, for the reaction given, the products have the large amount of gas, so by decreasing the pressure, more products will be formed, and the amount of NH₄HS will reduce. To decrease the pressure, we can increase the volume of the vessel: for the ideal gas equation (PV= nRT), pressure and volume are indirectly proportional.

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1 year ago

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Dafna1 [17]

We can calculate the mass percent of an element by dividing its atomic mass by the mass of the compound and then multiply by 100:
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2 years ago