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1 year ago

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Chemistry

1 answer:

evablogger [386]1 year ago

4 0

If 28.4 g of HgO decomposes and produces 2.0 g of oxygen, then 26 grams of Hg is produced.

<h3>What is decomposition reaction?</h3>

Decomposition reactions occur when complex chemical entities split apart into smaller components. Decomposition reactions often demand energy input.

There are three different kinds of breakdown reactions: thermal, photolytic, and electrolytic.

$Mass_{reactant$ = $Mass_{product}$

$Mass_{mercury oxide$ = $Mass_{mercury} + mass_{oxygen}$

28g = $mass_{mercury}$ + 2g

$mass_{mercury}$ = 26g

Thus, 28.4 g of HgO decomposes and produces 2.0 g of oxygen, then 26 grams of Hg is produced.

$percentage mass_{mercury} = \frac{mass_{mercury}}{mass_{mercury}oxide}$ X 100%

= 26g/28g

= 93%

thus 93% is the percent by mass of Hg present in HgO.

To learn more about Decomposition reaction, refer to the below link:

brainly.com/question/14112196

# SPJ1

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Word equation of nitrogen + oxygen —--> ammonia

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Answer:

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2 years ago

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What is the solution's freezing point: 15 g of CH4N2O (Molar mass = 60.055 g/mol) in 200. g of H2O? (Kf = 1.86 (°C·kg)/mol)

AURORKA [14]

Ok to answer this question we firsst need to fin the number of mol of Urea (CH4N2O). to do this we simply :

1 mol of urea =15/60.055 = 0.25mol

therefore 200g of water contain 0.25mol

the next step is to determine the malality of our solution in 200g of water, to do this we say:

200 g = 1Kg/1000g = 0.2kg

therefor 0.25mol/0.2Kg = 1.25mol/kg

and from the equation:

we know that i = 1

we are given Kf

b is the molality that we just calculated

therefore;

the solutions freezing point is -2.325°C

8 0

1 year ago

How do you find the amount of moles is .032 grams of water and whats the answer

masha68 [24]

Answer:

$\boxed {\boxed {\sf 0.0018 \ mol \ H_2 O }}$

Explanation:

First, we need to find the molecular mass of water (H₂O).

H₂O has:

2 Hydrogen atoms (subscript of 2)
1 Oxygen atom (implied subscript of 1)

Use the Periodic Table to find the mass of hydrogen and oxygen. Then, multiply by the number of atoms of the element.

Hydrogen: 1.0079 g/mol
Oxygen: 15.9994 g/mol

There are 2 hydrogen atoms, so multiply the mass by 2.

2 Hydrogen: (1.0079 g/mol)(2)= 2.0158 g/mol

Now, find the mass of H₂O. Add the mass of 2 hydrogen atoms and 1 oxygen atom.

2.0158 g/mol + 15.9994 g/mol = 18.0152 g/mol

Next, find the amount of moles using the molecular mass we just calculated. Set up a ratio.

$0.032 \ g \ H_2 O* \frac{ 1 \ mol \ H_2 O}{18.0152 \ g \ H_2 O}$

Multiply. The grams of H₂O will cancel out.

$0.032 * \frac{1 \ mol \ H_2 O}{18.0152 }$

$\frac{0.032 *1 \ mol \ H_2 O}{18.0152 }$

$0.00177627781 \ mol \ H_2 O$

The original measurement given had two significant figures (3,2). We must round to have 2 significant figures. All the zeroes before the 1 are not significant. So, round to the ten thousandth.

The 7 in the hundred thousandth place tells us to round up.

$0.0018 \ mol \ H_2 O$

There are about <u>0.0018 moles in 0.032 grams.</u>

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2 years ago

How many atoms are in<br> 3Ca(CIO3)2

satela [25.4K]

Answer:

Explanation:

Percent composition by element

Element Symbol # of Atoms

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2 years ago

Which statements are true concerning elements in the same group of the periodic table? Select all that apply.

Tatiana [17]

The statements A and F are true concerning elements in the same group of the periodic table.

To select all that apply, we need to evaluate each statement.

A. They have similar periodic properties.

This statement is true. All the elements in the same group will have similar chemical and physical properties due to the electron configuration of their outer shell. For example, the alkali metals group (Li, Na, K, Rb, Cs, and Fr), has a valence electron configuration of s¹ (in the outer shell), which gives them the tendency to react vigorously with water, as well as other properties.

B. They are all metals or nonmetals, but not both.

This is false. If we take a look at the p-block of the periodic table, we can see that the <u>groups</u> in this block are conformed by nonmetals, metals, and metalloids. For example, the icosagens group is formed by metalloids (B) and metals (Al, Ga, In, Tl).

C. They are either all solids or all liquids or all gases.

This is false. In some groups, all the elements are solids (alkaline earth metals) or gases (group of noble gases), but in others, the groups are conformed by gases with solids (pnictogens group) or by gases with liquids (halogens group).

D. They have the same number of shells of electrons.

This is false. In a group, the number of shells <u>increases from top to bottom</u> in the periodic table. For example, the electron configuration of the elements in the alkali metals is:

H: 1s¹
Li: [He]2s¹
Na: [Ne]3s¹
K: [Ar]4s¹
Rb: [Kr]5s¹
Cs: [Xe]6s¹
Fr: [Rn]7s¹

We can see that hydrogen has 1 shell and Cs has 6 shells.

E. They have the same number of inner core electrons.

This is false. As we said at point D, the number of shells increases from top to bottom in a group, so the number of inner core electrons also increases in this order. For example, in the alkaline earth metals group, the electron configuration of the elements is:

Be: [He]2s²
Mg: [Ne]3s²
Ca: [Ar]4s²
Sr: [Kr]5s²
Ba: [Xe]6s²
Ra: [Rn]7s²

As we can see, the number of inner shells increases from Be ([He]) to Ra ([Rn]).

F. They have the same outer shell electron configuration.

This is true. As we said at point A, the elements in the same group will have the same electron configuration of the outer shell (valence electron configuration). At points D and E, we can see that the valence electron configuration is the same for all the elements in the groups.

Therefore, statements A and F are true.

You can find more about the periodic table here: brainly.com/question/4287157?referrer=searchResults

I hope it helps you!

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3 years ago