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Fofino [41]
3 years ago
10

How many periods does the modern periodic table have?

Chemistry
1 answer:
dusya [7]3 years ago
8 0
There are 7 periods in the modern periodic table

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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
Why is the distance between New York and London increasing each year?
Dmitriy789 [7]

Answer:

because the tectonic plates move 4 inches per year.

Explanation:

8 0
3 years ago
Calculate the energy required to heat 566.0mg of graphite from 5.2°C to 23.2°C. Assume the specific heat capacity of graphite un
maw [93]

Answer:

7.23 J

Explanation:

Step 1: Given data

  • Mass of graphite (m): 566.0 mg
  • Initial temperature: 5.2 °C
  • Final temperature: 23.2 °C
  • Specific heat capacity of graphite (c): 0.710J·g⁻¹K⁻¹

Step 2: Calculate the energy required (Q)

We will use the following expression.

Q = c × m × ΔT

Q = 0.710J·g⁻¹K⁻¹ × 0.5660 g × (23.2°C-5.2°C)

Q = 7.23 J

6 0
3 years ago
What causes an increase in the reaction rate between molecules
Anestetic [448]
 molecules collide more frequently.

Chemical reaction mechanisms are based in the collision of molecules with certaing level of energy. More collisions implies grater probablity of reaction.
8 0
3 years ago
Read 2 more answers
Circle the letter next to each sentence that is true concerning the compressibility of gases. a. The large relative distances be
Anuta_ua [19.1K]

Answer:

The large relative distances between particles in a gas means that there is considerable empty space between the particles.

The assumption that particles in a gas are relatively far apart explains gas compressibility.

Compressibility is a measure of how much the volume of matter decreases under pressure.

Energy is released by a gas when it is compressed

Explanation:

The kinetic molecular theory establishes that gases are composed of molecules. These molecules of gas are far apart from each other hence there is a considerable empty space between the gas molecules. As a result of these empty spaces between gas molecules, it is possible to compress a gas.

Compressibility is defined as a measure of how much the volume of matter decreases under pressure. When a gas is compressed, work is done on the gas and energy is evolved hence the gas heats up.

6 0
3 years ago
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