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3 years ago

Why is melting an ice cube a reversible physical change?

Chemistry

1 answer:

Dmitriy789 [7]3 years ago

7 0

Answer:

Because you can freeze the water you melted back into a ice cube.

Explanation:

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What are the correct coefficients when this equation is balanced?

larisa86 [58]

4, 3, 1

Explanation:

Sb has four on the right, so it needs four on the left. It's all alone, so <u>4</u>.

O2 comes in pairs, so you only need <u>3</u> of those to get six oxygens.

And 1 is the place holder for the right side since we got the left to match perfectly.

6 0

3 years ago

What element has 47 protons in its nucleus?

sesenic [268]

Answer:

b). silver (Ag)

Explanation:

If you look at the periodic table, you just need to look at the atomic number of the element, because the atomic number tells you how many protons there are in the nucleus of the element.

But do be careful because some periodic tables have the molar mass at the top left corner, but the one I use has the atomic number at the top left corner, so make sure you look for the atomic number and not the molar mass.

5 0

3 years ago

if you react 28 grams of butene with excess hydrogen how many grams of butane would you expect to get

liberstina [14]

Answer:

The correct answer is 29 grams.

Explanation:

Based on the given question, the reaction will be,

CH3CH=CHCH3 + H2 ⇒ CH3CH2CH2CH3

The molecular weight of butene is 56 grams per mole, and the molecular weight of butane is 58 grams per mole.

Thus, it can be said that 56 grams of butene reacts with hydrogen gas and produces 58 grams of butane.

Therefore, 28 grams of butene when reacts with hydrogen gas to give,

= 58/56 * 28 = 29 grams of butane.

Hence, the mass of butane produced will be 29 grams.

8 0

3 years ago

Which of the following samples contains the greatest number of atoms?

mart [117]

Answer:

C. 11 moles of N2O

Explanation:

A. CO2 exists as a molecular compound. The number of atoms present = 1 atom of Carbon and 2 atoms oxygen = 3 atoms * 9 = 18 atoms

B. Xe exists as an atom. Number of atoms present = 10 * 1 atom = 10 atoms

C. N20 contains 3 atoms; 2 atoms of Nitrogen and 1 atom of oxygen.

Number of atoms present = 3 * 11 = 33 atoms

D. CO contains 2 atoms, 1 each of carbon and oxygen.

Number of atoms present = 12 * 2 = 24 atoms

7 0

3 years ago

A sample of seawater consists of water, sodium ions, chloride ions, and several other dissolved salts. These ions and salts are

stellarik [79]

Answer:

Mixture, homogeneous mixture, solution

Explanation:

A mixture is defined as a substance which is made by physical combination of two or more substance.

As in sea water, more than two substance are present, therefore is considered as mixture.

A mixture is considered as homogeneous mixture, if it has same proportion of components through out the mixture. In sea water proportions of all the components are same, therefore, its is also a homogeneous mixture.

In solution, solute is dissolved in a solvent and the concentration of the solute is same through out the solution.. In sea water, sodium ions, chloride ions, and several other salts are dissolved in water. Therefore, water is considered as solvents and components present are considered as solute.

so, sea water can also considered as solution.

Among the given options, 1, 3 and 4 are correct

So, sea water is considered as mixture, homogeneous mixture and solution.

6 0

3 years ago