Answer:
Explanation:
20.1 mL of .3 M KOH reacts with .38 g of sample monoprotic acid
20.1 mL of .3 M KOH = .021 x .3 mole of KOH
= .0063 mole of KOH
.0063 mole of KOH will react with .0063 mole of monoprotic acid
.0063 mole of monoprotic acid = .38 g
1 mole of monoprotic acid = 60.3 or 60 g
molecular weight of monoprotic acid = 60
Acid contains 1.6 % H , 22.2 % N , 76.2 % O
Ratio of weight of H , N , O in sample
= 1.6 : 22.2 : 76.2
Ratio of moles of H , N , O
1.6 / 1 : 22.2 / 14 : 76.2 / 16
1.6 : 1.585 : 4.76
= 1.6 / 1.585 : 1 : 4.76 / 1.585
= 1 : 1 : 3
Empirical formula
= HNO₃
Mol formula = 
( let )
Mol weight = n ( 1 + 14 + 3 x 16 )
= 63n .
Mol weight calculated above = 60
63n = 60
n = 1 ( approx )
Mol formula = HNO₃
Mol mass = 63 .
An indicator changes color when placed in an acidic solution
Periodic table is the representation of elements in an order
The history of periodic table can be summarized as
a) 1829 : Johann Dobereiner proposed the triad rule. According to him we can classify the elements in a triad where the atomic mass of middle element is average of atomic mass of the near by two atoms.
For example : Li, Na and K is a triad. Where atomic mass of Na is average of atomic mass of K
atomic mass of Na = 7+ 39 / 2 = 23
However, with the further discovery of elements the law was rejected.
b) 1864 : John Newland proposed the law of octave. According to him we can arrange the elements in a set of seven elements where the property of second set of seven elements will resemble the properties of first of seven elements or property will be repeated after seven elements. This was also rejected due to its limited applicability.
c) Meyer : He arranged some 28 elements into six different families based on their atomic masses. The members of each familiy shared some common properties.
d) 1869 : Mendleev : He actually developed a periodic table based on atomic mass of elements. He arranged the elements into groups and periods. He even left space for some undiscovered elements, which were later on discovered.
e) 1916 : Henry Moseley : He finally arranged elements based on their atomic number based on X-ray studies. He proposed the modern periodic law that the periodic properties of elements are due to atomic number of elements.
This is how you would do it. set up the rxn. balance, in this case you didn't need to. make a grid and cancel out units.
The four states of matter are solid, liquid, gas, and plasma.
Solid: a solid object has a definite volume and shape i.e. A box
Liquid: liquid has a definite volume but no definite shape i.e. Water
Plasma: plasma has some of the properties of gas but it's a good trainer of electricity and is a affected in a magnetic field i.e. A star
Gas: gas does not have a definite shape or volume so it takes the shoe of its container i.e. Balloon
