Answer:- Law of definite proportions.
Explanations:- The chemical composition of a compound is always constant means it contains the same elements in exactly same proportions by mass. This is called "Law of definite proportions."
Molecular formula of water is . It has two hydrogen atoms and one oxygen atom. Atomic mass of H is 1.008 and that of oxygen atom is 15.999.
Molar mass of water = 2(1.008) + 15.999 = 18.015
mass percentage of H = = 11.2%
mass percentage of O = = 88.8%
These percentages are always fix, no matter from where the sample of water is collected.
Answer:
Some elements are abbreviated with more than two letters such as the Ununtrium (Uut), Ununpentium (Uup), Ununseptum (Uus) and Ununoctio (Uuo).
Explanation:
Some elements have intuitive symbology, such as Chlorine (Cl), among others, which are represented by the first letters that make up the name. However, there are others who receive symbols that do not remember the name of the element, such as Lead (Pb). Regardless of the similarity between the names and the symbol of the elements, most of them have the symbol composed of one or two letters, except for the elements Ununtrium (Uut), Ununpentium (Uup), Ununseptum (Uus) and Ununoctio (Uuo).
B) element, molecule, compound, mixture is the answer just took the test ;) good luck : P
b. 0.04.
c. 0.05.
d. 0.08
This question is based on the concept of percentage by mass. Therefore the value of x, concentration of unknown ethanol solution is 4% when 20 gallons of a known solution is used. Option b is correct option
Mass percentage represents the the percentage of each element that is making a particular compound. Mass percentage does not have any unit as numerator and denominator contains the same unit.
Mathematically,
Percentage of mass = (component’s mass ÷ total mass) x 100%
According to the question the equation can be written as:
20× (x÷ 100) + 60×0.12 = 80× 0.10
x÷5 + 7.2 = 8
x÷ 5 = 0.8
x = 4%
concentration of unknown solution = 4%
Therefore, the value of x, concentration of unknown ethanol solution is 4% when 20 gallons of a solution is used. Option b is correct option
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the correct answer is B
(2) The mass of an electron is greater than the mass of a neutron.
(3) The mass of a proton is greater than the mass of an electron.
(4) The mass of a proton is greater than the mass of a neutron.
atoms are made of 3 types of subatomic particles - electrons, protons and neutrons
mass of proton is 1 atomic mass unit and proton is also 1 atomic mass unit
masses of protons and neutrons are very similar
mass of an electron is 1/1840th of 1 atomic mass unit
mass of electron is insignificant when compared to masses of neutrons and protons
protons and neutrons have a larger mass than electrons
from the given options correct answer is
(3) The mass of a proton is greater than the mass of an electron
Answer:
Ammonia has 4 regions of electron density around the central nitrogen atom (3 bonds and one lone pair). These are arranged in a tetrahedral shape. The resulting molecular shape is trigonal pyramidal with H-N-H angles of 106.7°.
Explanation: