What is the most important change in a chemical change?

One atom of silicon can properly be combined in a compound with

julia-pushkina [17]

Answer:

C. two atoms of oxygen.

Explanation:

Step 1: Data given

Silicon has 14 electrons

Silicon is part of Group IV, all the elements there have 4 valence electrons.

It can form a compound when 4 valence electrons bind with the 4 valence elctrons of silicon

A. four atoms of calcium.

Calcium has 2 valence elctrons. 4 atoms of calcium cannot bind on 1 atom of silicon since there are only 4 valence electrons.

B. one atom of chlorine.

1 atom of chlorine has 7 valence electrons. Chlorine can bind with an atom with 1 valence electron. Since silicon has 4 valence electrons, they will not bind.

Silicon can bind with 4 atoms of chlorine to form SiCl4

C. two atoms of oxygen.

Oxygen has 6 valence electrons, this means oxygen can bind with an element with 2 valence electrons.

Since silicon has 4 valence electrons, it can bind with 2 atoms of oxygen to form SiO2 (silicon dioxide).

D. three atoms of hydrogen.

Hydrogen has 1 valence electron. 1 hydrogen atom can bind with an element that has 7 valence electrons.

Three atoms of hydrogen can bind with an element that has 5 valence electrons.

Silicon will not bind with 3 atoms of hydrogen ( but can bind with 4 atoms of hydrogen)

5 0

4 years ago

What is the predicted change in the boiling point of water when 1.50 g of

dezoksy [38]

Answer:

0.00735°C

Explanation:

By seeing the question, we can see the elevation in boiling point with addition of BaCl₂ in water

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$\textsf {While} \: \sf {\Delta T_b} \: \textsf{expression is used} \\ \textsf {for elevation of boiling point}$

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The elevation in boiling point is a phenomenon in which there is increase in boiling point in solution, when the particular type of solute is added to pure solvent.

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$\sf \large \underline{The \: formula \: to \: be \: used \: in \: this \: question \: is} \\ \boxed{T_b = i \times K_b \times m}$

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Where 'i' is van't hoff factor which represents the ratio of observed osmotic pressure and the value to be expected.

and 'i' is 3 (as given in the question)

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'Kb' is molal boiling point constant. And it's value is 0.51°C/mol(given in question)

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'm' represent the molality of solution. Molatity is no. of moles of solution present in 1kg of solution.

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To find molality, we have to divide no. of moles of solute by weight of solution

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While first we need to no. of moles

$\sf \implies no. \: of \: moles = \frac{weight \: of \: solute}{molar \: mass \: of \: solute} \\ \\ \implies \sf no. \: of \: moles = \frac{1.5}{208.23} \\ \\ \sf \implies no. \: of \: moles = 0.0072$

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Now, we will find molality

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$\sf \hookrightarrow molality = \frac{no.\: of \: moles}{weight \: of \: solution} \\ \\ \sf \hookrightarrow molality = \frac{0.072}{1.5} \\ \\ \sf \hookrightarrow molality = 0.048 \: mol {kg}^{ - 1}$

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$\textsf{ \large{ \underline{Now substituting the required values}}}$

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$\sf \longmapsto \Delta T_b = 3 \times 0.51 \times 0.0048 \\ \\ \\ \boxed{ \tt{ \longmapsto \Delta T_b =0.00735{ \degree}C}}$

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Henceforth, the change in boiling point is 0.00735°C.

7 0

2 years ago

Enter your answer in the provided box. Calculate the number of moles of CrCl, that could be produced from 49.4 g Cr202 according

Mrrafil [7]

Answer:

0.4694 moles of CrCl₃

Explanation:

The balanced equation is:

Cr₂O₃(s) + 3CCl₄(l) → 2CrCl₃(s) + 3COCl₂(aq)

The stoichiometry of the equation is how much moles of the substances must react to form the products, and it's represented by the coefficients of the balanced equation. So, 1 mol of Cr₂O₃ must react with 3 moles of CCl₄ to form 2 moles of CrCl₃ and 3 moles of COCl₂.

The stoichiometry calculus must be on a moles basis. The compounds of interest are Cr₂O₃ and CrCl₃. The molar masses of the elements are:

MCr = 52 g/mol

MCl = 35.5 g/mol

MO = 16 g/mol

So, the molar mass of the Cr₂O₃ is = 2x52 + 3x35.5 = 210.5 g/mol.

The number of moles is the mass divided by the molar mass, so:

n = 49.4/210.5 = 0.2347 mol of Cr₂O₃.

For the stoichiometry:

1 mol of Cr₂O₃ ------------------- 2 moles of CrCl₃

0.2347 mol of Cr₂O₃----------- x

By a simple direct three rule:

x = 0.4694 moles of CrCl₃

6 0

3 years ago

What is bed rock made of

Darya [45]

Answer:

Bedrock is the hard, solid rock beneath surface materials such as soil and gravel.

Bedrock can be made of most types of rock, such as granite, limestone, or sandstone.

Hope this helps!

8 0

3 years ago

Read 2 more answers

How many moles of CCI are there in 78.2 g of CCI.?

vaieri [72.5K]

Answer:

0.508 mole

Explanation:

NOTE: Since no hydrogen is attached to the compound given in question above, it means the compound is CCl₄.

The number of mole present in 78.2 g of CCl₄ can be obtained as follow:

Mass of CCl₄ = 78.2 g

Molar mass of CCl₄ = 12 + (35.5×4)

= 12 + 142

= 154 g/mol

Mole of CCl₄ =?

Mole = mass / molar mass

Mole of CCl₄ = 78.2 / 154

Mole of CCl₄ = 0.508 mole

Therefore, 0.508 mole is present in 78.2 g of CCl₄

6 0

3 years ago