Answer:
Most metals have <u>luster</u> which means they <u>reflect</u> light
Explanation:
When light, which is made up of energetic photons, comes in contact with the surface of a metal, it is absorbed due to the corresponding energy gaps present between the metal orbital. The absorbed photons results in the raising of the energy levels of electrons within an atom of the metal which later drop back to a lower energy level and re-emit the photons which can now be observed as the metallic luster.
Answer:
Hypothesis---experiments----results----conclusion.
Explanation:
First we make a hypothesis means a statement about why the tree looks unhealthy. In this segment of scientific method we have to test the hypothesis through experimentation. After that we have to take the readings of various parts of the tree and analyze the data to find out the problem. In the next step, we have to made the results on the basis of the data that is obtained. In the last we have to write the conclusion of the analysis and see the hypothesis.
Answer:
3.2043 x 10²³
Explanation:
No. of Mole of lead (Pb) = 0.532 mol
No. of atoms of lead = ?
Solution:
Formula Used to calculate
no. of moles = numbers of particles (ions, molecules, atoms) /Avogadro's number
Avogadro's no. = 6.023 x10²³
So,
The formula could be written as
no. of atoms of lead Pb = no. of moles x 6.023 x10²³
Put the values in above formula
no. of atoms of lead Pb = 0.532 mol x 6.023 x10²³
no. of atoms of lead Pb = 3.2043 x 10²³
so 3.2043 x 10²³ atoms of lead are contained in 0.532 mole.
Answer:
Thermal decomposition or cracking
Explanation:
Petroleum is a mixture of hydrocarbons which are usually formed naturally. Petroleum undergo a host of chemical reactions. One of such is thermal decomposition or cracking.
Cracking is used in the petroleum industry to covert heavy fractions to more useful lighter ones.
When petroleum is subjected to high temperature and pressure, and in the presence of catalyst, the long chain type of petroleum will decompose into more useful smaller and lighter molecules.
Example is given below:
C₁₅H₃₂ → C₈H₁₈ + C₃H₆ + 2C₂H₄
