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3 years ago

Sort the phrases pertaining to pure substances and mixtures as either true or false.

1 answer:

5 0

You have to note that pure substances can be elements or compounds. There is only one component all throughout. On the other hand, a mixture is a combination of different elements and compounds. They can appear in different phases. For example, air is a mixture. It is composed of pure substances of oxygen, carbon dioxide, and nitrogen.

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Classify which compounds will dissolve in water and which ones will not dissolve in water.

vredina [299]

Answer:

Dissolves in water: Acetone, 1-propanol, Methanol

Do not dissolve in water: Hexane, Decane

Explanation:

From the principle that like dissolves like,polar substances will dissolve in polar solutions, while non-polar substances will dissolve in non-polar substances.

Water is a polar solution, therefore, polar substances will dissolve in it.From the given options:

Acetone is a polar molecule, therefore, it will dissolve in water.

1-propanol is a polar molecule, therefore, it will dissolve in water.

Hexane is a non-polar molecule, therefore, it will not dissolve in water.

Methanol is a polar molecule, therefore, it will dissolve in water.

Decane is a non-polar molecule, therefore, it will not dissolve in water

6 0

3 years ago

iron will react with oxygen to produce Fe2O3. how many grams of Fe2O3 will he produced if 0.18 mil of Fe reacts?

nasty-shy [4]

Answer:

14.4g

Explanation:

First, we need to write a balanced equation for the reaction between Fe and O2 to produce Fe2O3. This is illustrated below:

4Fe + 3O2 —> 2Fe2O3

From the balanced equation,

4moles of Fe produced 2moles of Fe2O3.

Therefore, 0.18mol of Fe will produce = (0.18x2) /4 = 0.09mol of Fe2O3.

Now we need to find the mass present in 0.09mol of Fe2O3. This can be achieved by doing the following:

Molar Mass of Fe2O3 = (56x2) + (16x3) = 112 + 48 = 160g/mol

Number of mole of Fe2O3 = 0.09mol

Number of mole = Mass /Molar Mass

Mass = number of mole x molar Mass

Mass of Fe2O3 = 0.09 x 160 = 14.4g

6 0

2 years ago

The table below shows the height of a ball x seconds after being kicked.

irga5000 [103]

Answer:

-16

Explanation:

8 0

2 years ago

Read 2 more answers

Explain why a wooden spoon is a better choice than a metal spoon for stirring a boiling pot of soup

PtichkaEL [24]

A wooden spoon insulates itself and retains no heat, a mental spoon would retain heat, and probably burn your hand<span />

7 0

3 years ago

Why isn't carbon-14 dating accurate for estimating the age of materials older than 50,000 years?

soldi70 [24.7K]

Carbon-14 is radioactive isotope of carbon.
Carbon is essential element of living cells. While the living cells are alive, the carbon contained in them are in equilibrium with the carbon in atmosphere. But, once the cell dies, the carbon-14 isotope undergoes radioactive decay. By measuring the carbon-14 in atmosphere to the carbon-14 in dead organism, we can calculate the time (or years) that organism have died.

However, carbon-14 dating technique is not accurate for estimating the age of materials older than 50,000 years old (above 40,000 years). This is because, 99% of carbon is carbon-12, 1% is carbon-13 and trace remaining is the carbon-14. This means, carbon-14 is found in very trace amount, in fact 1 part per trillion of carbon atoms present is carbon-14. The half of life of carbon-14 is 5,730 years. For dating the organism, we use the concept of half lives of the carbon-14 isotope in the dead organisms and calculate how many half life old the sample is. But as the years increases, the number of carbon-14 isotope becomes too low to detect and make accurate calculation.
This means, at some point the organism can simply run out of carbon-14.

Hence carbon-14 dating is not accurate for estimating age of materials older than 50,000 years old.

5 0

3 years ago