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zhenek [66]
3 years ago
8

In any chemical compound, the elements are always combined in the same proportion by ___. A. charge B. mass C. volume D. density

Chemistry
1 answer:
Tresset [83]3 years ago
6 0

Answer is: B. mass.

Proust's law or law of constant composition said that a given chemical compound always contains its component elements in fixed ratio and does not depend on method of preparation.

Law of multiple proportions or Dalton's Law said that the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.  

For example, nitrogen(I) oxide N₂O; m(N) : m(O) = 2·14 : 16 = 7 : 4.

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ΔH for the formation of CuCl2 from its elements is -220.1 kJ/mol. How many kJ are associated with the formation of 0.30 mole of
otez555 [7]
0.3 * - 220.1 = - 66.03kJ
3 0
3 years ago
Read 2 more answers
Predict whether ΔS° is greater than, less than, or approximately zero for each of the following reactions, and explain your choi
inna [77]

Answer:

Explanation:

Entropy -

In a system, the randomness is measured by the term entropy .

Randomness basically refers as a form of energy that can not be used for any work.

The change in entropy is given by amount heat per change in temperature.

  • When solid is converted to gas entropy increases,

As the molecules in solid state are tightly packed and has more force of attraction between the molecules, but as it is converted to gas, the force of attraction between the molecule decreases and hence entropy increases.

So,

The particles of the substance , if are tightly held by strong force of attraction will decrease the entropy ,

And

If the particles are loosely held , the entropy will increase .  

  • If in a reaction , more number of gaseous atoms are present in the product side , entropy will increase , i.e. Δ°S > 0
  • When liquid is converted to solid entropy decreases,  

As the molecules in liquid state are loosely packed and has less force of attraction between the molecules, but as it is converted to solid, the force of attraction between the molecule increases and hence entropy decreases.

  • If in a reaction , less number of gaseous atoms are present in the product side , entropy will decrease , i.e. Δ°S < 0

From the question ,

( a )  NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)

Gaseous atoms -

Reactant - 1 + 5 = 6

Product - 4 + 6 = 10 ,

Hence ,

More number of gaseous atoms are present in the product side , So ,

entropy will increase , i.e. Δ°S > 0

( b ) CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g)

Gaseous atoms -

Reactant - 1 + 2 = 3

Product - 1 + 2 = 3 ,

Since ,

Both the side the value of gaseous atoms are , hence , Δ°S = 0 .

( c ) CaCO₃(s) → CaO(s) + CO₂(g)

Gaseous atoms -

Reactant = 0

Product - 0 + 1 = 1 ,

Since ,

Hence ,

More number of gaseous atoms are present in the product side , So ,

entropy will increase , i.e. Δ°S > 0

8 0
3 years ago
Which term represents the fixed proportion of elements in a compound
Gekata [30.6K]

Answer:

Chemical formula.

Explanation:

A chemical formula have fix proportion of atoms of elements.

Chemical formula:

A chemical formula is the way of presenting the chemical proportion of atoms of those elements, that combine to form a compound.

For example:

Water consist of two atom of hydrogen and one atom of oxygen. The atoms of both elements combine to form a compound i.e water. The atoms of both elements always combine in a fixed ratio which is 2:1 in molecule of water.

H₂O

2:1

Carbon dioxide consist of two atom of oxygen and one atom of carbon. The atoms of both elements combine to form a compound i.e carbon dioxide. The atoms of both elements always combine in a fixed ratio which is 1:2 in molecule of carbon dioxide .

CO₂

1;2

5 0
3 years ago
According to the Arrhenius definitions of acids and bases, choose the acids from the list of acids and bases. Check all that app
ANEK [815]

Answer:

The answers are:

  • HBr
  • HClO
  • H2S

8 0
3 years ago
A metal sample is heated and placed into the water in a calorimeter at room temperature. Which statement best describes how the
rjkz [21]

Answer:

Energy transfers from the metal to the water and calorimeter until they are all at room temperature.

Explanation:

Calorimetry is the process that is used to determine the amount of heat that has been transferred in any process. In any chemical or physical process, the amount of energy is required. This energy is measured by the process of calorimetry. A calorimeter is a device that is used in this process. The heat that has been used in the process is measured and the change in the temperature is noted.

8 0
3 years ago
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