Answer:
Explanation:
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
For example:
In given photosynthesis reaction:
6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂
there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.
Law of multiple proportion:
When two elements combine to form two or more compounds with different proportions, the weight of on element that combine with other elements in fixed proportion is in the ratio of small whole number.
For example:
Consider the example of carbon dioxide and carbon monoxide.
CO and CO₂
we are given with 1 g carbon on both case while 1.3 g oxygen for carbon monoxide and 2.6 for carbon dioxide. It means the ratio of oxygen is 1:2.
There is 1.3 g of oxygen in carbon monoxide for one g of carbon while in case of carbon dioxide there is 2.6 g of oxygen for one gram of carbon.
Answer:
250 g of sodium chloride have 4.3 moles
Explanation:
Given data:
Mass of NaCl = 250 g
Number of moles = ?
Solution:
Number of moles = mass/ molar mass
Number of moles = 250 g/ 58.5 g/mol
Number of moles = 4.3 moles
Thus 250 g of sodium chloride have 4.3 moles.
That looks like cells of a multicellular organism, so B.
In a chemical bonding the electrons that are in the outer most orbital are the one's involved in bonding. The aim of bonding is that each of the atoms must have an octet of electons ( but there are exception which do not follow this rule ) in their valence orbital in order to become stable.Atoms can either loses, gain or share electrons in order to reach this desired state. In a case where they share, they might share all their valence electrons either with the same or different atoms or a certain number of their electron which will end up with them having eight electrons in their valence orbital. Once the atoms have bonded, the remaining electrons that are not shared between the atoms are called the unshared elctron pair and the electrons that are shared and involved in forming bonds are called the shared electron pair. the unshared electron pair can be shared with another atom that has lost it's electrons, this pair is then called a lone pair.