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Black_prince [1.1K]
3 years ago
8

Select the two statements that are TRUE about compounds

Chemistry
1 answer:
patriot [66]3 years ago
4 0

a) a compound always contains at least 2 elements

is the answer

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What is the Lewis dot diagram structure for PI2F
Brut [27]

Answer:

Please find attached the completed Lewis dot diagram structure for PI₂F

Explanation:

The number of valence electrons are;

Phosphorus = 5 Electrons

Iodine = 2 × 7 electrons = 14 electrons

Chlorine = 7 electrons

The total number of valence electrons = 14 + 7 + 5 = 26 electrons

2) We draw the symbol that represents the basic (general) structure of the molecule as follows;

The sheared electron pair are represented by single bond lines

3) We complete the octet structures round the fluorine and the iodine atoms as attached showing 18 electrons plus 6 shared electron pairs, with a maximum from step 2 to give a total of (18 + 6) 24 electron pairs

4) We add the 2 unaccounted valence electron on the phosphorus atom to give it the stable octet structure, which gives the completed Lewis structure

3 0
3 years ago
What are the primary products of burning a fossil fuel?
denis23 [38]
<span>Several important pollutants are produced by fossil fuel combustion: carbon monoxide, nitrogen oxides, sulfur oxides, and hydrocarbons. In addition, total suspended particulates contribute to air pollution, and nitrogen oxides and hydrocarbons can combine in the atmosphere to form tropospheric ozone, the major constituent of smog.

Carbon monoxide is a gas formed as a by-product during the incomplete combustion of all fossil fuels. Exposure to carbon monoxide can cause headaches and place additional stress on people with heart disease. Cars and trucks are the primary source of carbon monoxide emissions.

Two oxides of nitrogen--nitrogen dioxide and nitric oxide--are formed in combustion. Nitrogen oxides appear as yellowish-brown clouds over many city skylines. They can irritate the lungs, cause bronchitis and pneumonia, and decrease resistance to respiratory infections. They also lead to the formation of smog. The transportation sector is responsible for close to half of the US emissions of nitrogen oxides; power plants produce most of the rest.

Sulfur oxides are produced by the oxidization of the available sulfur in a fuel. Utilities that use coal to generate electricity produce two-thirds of the nation's sulfur dioxide emissions. Nitrogen oxides and sulfur oxides are important constituents of acid rain. These gases combine with water vapor in clouds to form sulfuric and nitric acids, which become part of rain and snow. As the acids accumulate, lakes and rivers become too acidic for plant and animal life. Acid rain also affects crops and buildings.

Hydrocarbons are a broad class of pollutants made up of hundreds of specific compounds containing carbon and hydrogen. The simplest hydrocarbon, methane, does not readily react with nitrogen oxides to form smog, but most other hydrocarbons do. Hydrocarbons are emitted from human-made sources such as auto and truck exhaust, evaporation of gasoline and solvents, and petroleum refining.

The white haze that can be seen over many cities is tropospheric ozone, or smog. This gas is not emitted directly into the air; rather, it is formed when ozone precursors mainly nonmethane hydrocarbons and nitrogen oxides react in the presence of heat and sunlight. Human exposure to ozone can produce shortness of breath and, over time, permanent lung damage. Research shows that ozone may be harmful at levels even lower than the current federal air standard. In addition, it can reduce crop yields.

Finally, fossil fuel use also produces particulates, including dust, soot, smoke, and other suspended matter, which are respiratory irritants. In addition, particulates may contribute to acid rain formation.

Also, water and land pollution.

</span>
5 0
3 years ago
Read 2 more answers
After 11.5 days, 12.5% of a sample of radon-222 that originally weighed 42g remains. What is the half-life of this isotope?
Bond [772]
Half-life is defined as the amount of time it takes a given quantity to decrease to half of its initial value.  The equation to describe the decay is
Nt=N0(1/2) ^{t/t(1/2)}  where N0 is the initial quantity, Nt is the remaining quantity after time t, t1/2 is the half-time.  So work out the equation, t1/2 = t (-ln2)/ln(Nt/N0) = 11.5*(-ln2)/ln(12.5/100) = 3.83 days
5 0
3 years ago
rusting of steel can be prevented by coating the steel with a layer of zinc. Explain, in terms of electron transfer, why steal d
Luba_88 [7]

Answer:

Wouldn't rust because zinc will lose electrons more readily than iron and will therefore oxidize first.

Explanation:

This process whereby rusting of steel is prevented by coating the steel with a layer of zinc is known as galvanization.

Now, in this process, the steel object will be coated in a thin layer of zinc. This coating will prevent oxygen and water from reaching the underneath metal since the zinc will also act as a sacrificial metal.

Now, Zinc is used because it has a lower reduction potential than iron and thus it will get easily more oxidized than iron. Which means the zinc will lose electrons more readily than iron.

Also, since zinc has a lower reduction potential, it is therefore the more active metal. Thus, even if the zinc coating is scratched and the steel is exposed to moist air, the zinc will still get to oxidize before the iron.

7 0
3 years ago
Describe the formation of ions by electron loss or gain
Ronch [10]

Explanation:

Ions form when atoms gain or lose electrons. This is so that they form a full outer shell of electrons. When an atom gains electrons it becomes a negative ion, because electrons are negatively charged. For example, all halogens (group 7 or 17) form negative ions as they gain an electron forming a 1- charge. When an atom loses electrons it becomes a positive ion, as it is losing some negative charge from the electrons. This would be for example, alkali metals (group 1) which lose an electron to form a positive ion with a 1+ charge, (ALL metals form positive ions).

6 0
2 years ago
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