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Tomtit [17]
3 years ago
5

Why do metals change in appearance over time?

Chemistry
1 answer:
gogolik [260]3 years ago
5 0

The exterior surface of metal can be changed by many chemical reaction takes place the reaction is carried out by presence of oxygen and water in air which Demage shiny surface of metal. The other processes can also be involved as pollution, moisture and environmental change can also effect on the surface of metal.

If metal is keept in open environment for a long time moisture contents in air boats the corrosion and rusting of metal processes.

Hopefully you will understand.

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How many moles of sulfur dioxide are in 2.26x10^33 sulfur dioxide molecules?
Alexus [3.1K]

Answer:moles = no. of molecules / Avogadro's number

          = 2.26 x 10^33 / 6.022 x 10^23

          = 3752906011

Round to significant figures which is 3 = 3.75 x 10^9 mol

Explanation:

The formula for finding how many moles of a substance when given the amount of molecules is: moles = number of molecules / Avogadro's number

3 0
3 years ago
Read 2 more answers
For the reaction PC15 (8) PC13 (g) + Cl2 (g) K = 0.0454 at 261 °C. If a vessel is filled with these gases such that the initial
Fiesta28 [93]

Answer:

The correct answer is B.

The K_{eq} is samller than Q of the reaction . So,the reaction will shift towards the left i.e. towards the reactant side.

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as K_{eq}

K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

PCl_5(g)\rightleftharpoons PCl_3(g)+Cl_2(g)

The expression for Q is written as:

Q=\frac{[PCl_3][Cl_2]}{[[PCl_5]^1}

Q=\frac{0.20 M\times 2.5 M}{0.20 M}

Q=2.5

Given : K_{eq} = 0.0454

Thus as K_{eq}, the reaction will shift towards the left i.e. towards the reactant side.

4 0
3 years ago
Read 2 more answers
When heated to 150 ºC, CuSO4.5 H2O loses its water of hydration as gaseous H2O. A 2.50 g sample of the compound is placed in a s
Katyanochek1 [597]

Answer:

Water pressure 0.5 atm

Total Pressure= 2.27  atm

Explanation:

To answer this problem, one has to realize that there are two processes that increase the temperature of the sealed vessel.

First, the dry air in the sealed vessel will be heated which will cause its pressure to increase and it can be determined by the equation:

P₁ x T₂   = P₂ x T₁  ∴  P₂ =  P₁ x T₂ / T₁

For the second process, we have an amount of n moles of water which will be released when the copper sulfate is heated. In this case, to determine the value of the the water gas we will use the gas law:

   PV = nRT  ∴ P =  nRT/V

n will we calculated from the quantity of sample.

2.50 g  CuSo₄ 5H₂O x  1 mol/ 249.69 g = 0.01 mol CuSo₄ 5H₂O

the amount water of hydration is

= 0.01 mol CuSo₄ 5H₂O * 5 mol H₂O / 1 mol CuSo₄ 5H₂O

= 0.05 mo H₂O

pressure of dry air at the final temperature,

P₂ = 1 atm x 500 K/ 300 K = 1.67 atm

Pressure of water :

P (H₂O) 0.05 mol x 0.08206 Latm/kmol x 500 K/ 4 L = 0.5 atm

∴ Total Pressure =  1.67 atm

H2O Pressure = 0.5 atm

5 0
3 years ago
How much heat is required to raise the temperature of 50.0g of water 13°C<br>​
N76 [4]

Answer:one gram by 1oC

Explanation: you will need to know the value of water's specific heat

3 0
3 years ago
In the world of chemistry, a 'mole' is a number of something... a very large number of something.
kipiarov [429]

Given:

No of atoms present= 8.022 x 10^23 atoms

Now we know that 1 mole= 6.022 x 10^23 atoms


Hence number of moles present in 8.022 x 10^23 atoms is calculated as below.

Number of moles

= 8.022 x 10^23/6.022x 10^23

=1.3 moles.

Hence we have 1.3 moles present.

3 0
3 years ago
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