Answer:
Explanation:
a. change of colour:
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. The products have different molecular structures than the reactants. Different atoms and molecules radiate different colours of light. Hence, there usually is a change in colour during a chemical reaction.
Eg: copper reactions with the elements
b. Evolution of gas:
A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide.
Eg: ammonium hydroxide breaks down to water and ammonia gas.
c. Change of smell :
Production of an Odor Some chemical changes produce new smells. ... The formation of gas bubbles is another indicator that a chemical change may have occured.
Eg: The chemical change that occurs when an egg is rotting produces the smell of sulfur.
d. Change of state:
A chemical reaction is a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products.
Eg: candle wax (solid) melts initially to produce molten wax (liquid)
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Answer:
the wavelength, in nm, of the photon is 487.5 nm
Explanation:
Given:
n = 4 (excited)
n = 2 (relaxes)
Question: Calculate the wavelength, in nm, λ = ?
First, it is important to calculate the energy of the electron when it excited and then when it relaxes.
(excited)
(relaxes)
The change of energy
ΔE = E₁ - E₂=-0.85 - (-3.4) = 2.55 eV = 4.08x10⁻¹⁹J
For a photon, the wavelength emitted
Here
h = Planck's constant = 6.63x10⁻³⁴J s
c = speed of light = 3x10⁸m/s
Substituting values:
Carbon dioxide + water → glucose + oxygen + water
Answer:
yes
Explanation:
The five senses: sight, hearing,
taste, smell, and touch can be extended with instruments
Balanced chemical equation: S(s) + O₂(g) → SO₂(g).
Sulfur change oxidation number from 0 to +4 (oxidation) and oxygen change oxidation number from 0 to -2 (reduction).
Sulfur dioxide (SO₂) is very common volcanic gas.
Fossil fuel combustion increases the acidity of rain because the sulfur dioxide is produced.
Because of fuel combustion, sulfur dioxide goes up into the atmosphere as the hot gases rise, than it reacts with water and oxygen in the air and form sulfuric acid.
