Answer:
The formula of Quartz is SiO2. So, 1 mole of Quartz will have 2 moles of oxygen atoms, i.e. 2 x 6.022 x 10^23 atoms of oxygen. The molar mass of quartz is 60 g per mol. So, 60 g quartz means 1 mole quartz.
Explanation:
Answer:
c
Explanation:
when the river is affected by the acid rain many species go into extinction
The balanced half reactions are
4 Fe2+ ====> 4 Fe3+ + 4 e-
<span>MnO42- + 8 H+ + 4 e- ===> Mn2+ + 4 H2O
The net ionic equation is
4 Fe2+ + </span>MnO42- + 8 H+ ===> 4 Fe3+ + Mn2+ + 4 H2O<span />
Answer:
The correct options are:
1) Pure chemical substance
2) Element.
Explanation:
each of the term is explained below:
1) <u>Mixture: </u> Since tungsten is an element in periodic table thus it is not a mixture.
2) False by definition of mixture.
3) false by definition of mixture.
4) <u>Solution:</u> Tungsten in a filament is in solid form hence solution is incorrect.
5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.
6) <u>Compound:</u> By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.
7) Tungsten is a element in the periodic table with atomic number 74.
There are two terms
a) accuracy : it relates to the exactness of an answer that how an answer is close to the actual answer or actual reading
So 104.6 is accurate
b) Precision : This is related to the closeness of different readings with each other
The first reading is 103.7 and the second one is 108.4 so the second reading is quite different from the first reading so it cannot be called as precised
Again 105.8 has good difference from the second reading hence again this is not precised
However the last reading 104.6 is quite near to 105.8 so 104.6 can be called as precise
