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3 years ago

If 6.02×1023 atoms of element Y have a mass of 28.09 g, what is the identity of Y?

Chemistry

1 answer:

Mazyrski [523]3 years ago

8 0

Silicon is the element having a mass of 28.09 g

Explanation:

Silicon is the element having an atomic mass of 28.09 g / mol. So 28.09 g of silicon contains 6.023 $\times$ 10^23 atoms. One mole of each element can produce one mole of compound.

The Atomic weight of an element can be determined by the number of protons and neutrons present in one atom of that element. So atomic weight expressed in grams always contain the same number of atoms( 6.023 $\times$ 10^23).

Avagadro number is the number of atoms of 1 mole of any gas at standard temperature and pressure. It has been determined that 6.023 $\times$ 10^23 atoms of an element are equal to the average atomic mass of that element.

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What do you call the repetitive motion of a wave (such as the way a cork may bob up and down in the ocean)?

matrenka [14]

Answer is periodic because only happens in certain times

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2 years ago

The half-life of radon-222 is 3.8 days. If a sample currently contains 3.1 grams of radon-222, how much radon-222 did this sampl

vodka [1.7K]

The number of grams of radon 222 did it have 15.2 ago was 49.6 grams( answer C)

calculation

calculate the number of half life it has covered from 15.2 days to 3.8 days

that is divide 15.2/ 3.8 = 4 half life

half life is time taken for a radio activity of a specified isotope to fall to half its original mass

therefore 3.8 days ago it was 3.1 x2 = 6.2 grams

7.6 days ago it was 6.2 x2 = 12.4 grams

11.4 days ago it was 12.4 x2= 24.8 grams

15.2 days ago it was 24.8 x2=49.6 grams

5 0

2 years ago

three moles of sodium carbonate are mixed with two moles of lead nitrate in aqueous solution, leading to formation of a solid pr

aleksandrvk [35]

There are 4 moles of spectator ions that remain in solution.

The equation of the reaction is;

Na2CO3(aq) + Pb(NO3)2(aq) -------> PbCO3(s) + 2NaNO3(aq)

We have to determine the limiting reactant. This is the reactant that yields the least amount of product. Note that the spectator ions are Na^+ and NO3^- that form NaNO3.

For Na2CO3

1 mole of Na2CO3 yields 2 moles of NaNO3

3 moles of Na2CO3 yields 3 × 2/1 = 6 moles of NaNO3

For Pb(NO3)2

1 mole of Pb(NO3)2 yields 2 moles of NaNO3

2 moles of Pb(NO3)2 yields 2 × 2/1 = 4 moles of NaNO3

We can see that Pb(NO3)2 is the limiting reactant.

Since [NaNO3] = [Na^+] = [NO3^-], it follows that there are 4 moles of spectator ions that remain in solution.

Learn more: brainly.com/question/22885959

6 0

2 years ago

No links please. How many moles of methane (CH4) are in 7.31x10^25 molecules?

ad-work [718]

Answer:

molar mass of methane CH4

= C + 4 H

= 12.0 + 4 x 1.008

= 12.0 + 4.032

= 16.042g/mol

7.31 x 10^25 molecules x 1 mole CH4 = 121.43 moles

6.02 x 10^23 CH4 molecules

121.43 moles CH4 are present.

Explanation:

not to certain if this is right or not.. but hope it helps!

4 0

2 years ago

A reaction is exothermic when Group of answer choices weak bonds break and strong bonds form. strong bonds break and weak bonds

Leona [35]

Answer:

weak bonds break and strong bonds form

Explanation:

An exothermic reaction is a chemical reaction in which heat energy is evolved during the reaction process.

Bond formation requires energy while bond breakage releases energy. More energy is needed for the formation of weak bonds as compared to strong bonds.

Hence, when weak bonds break, they release more energy than needed to make a corresponding strong bond leading to the release of the remaining energy as heat.

6 0

3 years ago