Answer:
1
all matter is made of tiny particles called atom
Answer:
A. Compounds
Explanation:
Firstly, don't let the word "pure" confuse you; this is pretty much irrelevant to the question.
The key to answering this question lies in "substance" and "more than one type of element chemically bonded."
Something you ought to memorize is that a substance is either an element or compound. Therefore, you can eliminate choices B./C.
Next, use the part of the definition that says "more than one type of element chemically bonded" to conclude that it's a compound. Not only is this the definition of a compound, but the fact that is says <em>more than one type of element</em> should automatically tell you that it is different from just a regular element (Choice D.).
Explanation :
As we know that Mendeleev arranged the elements in horizontal rows and vertical columns of a table in order of their increasing relative atomic weights.
He placed the elements with similar nature in the same group.
According to the question, the atomic weight of iodine is less than the atomic weight of tellurium. So according to this, iodine should be placed before tellurium in Mendeleev's tables. But Mendeleev placed iodine after tellurium in his original periodic table.
However, iodine has similar chemical properties to chlorine and bromine. So, in order to make iodine queue up with chlorine and bromine in his periodic table, Mendeleev exchanged the positions of iodine and tellurium.
As we know that the positions of iodine and tellurium were reversed in Mendeleev's table because iodine has one naturally occurring isotope that is iodine-127 and tellurium isotopes are tellurium-128 and tellurium-130.
Due to high relative abundance of tellurium isotopes gives tellurium the greater relative atomic mass.
Nickel contains more atoms.
<u>Explanation:</u>
Number of atoms is determined by the Avogadro number.
1 mole of substance contains 6.022 X 10²³ atoms.
Given:
Mass of Nickel, Ni = 3.89g
Molecular weight of Ni = 58.6934g
Number of moles of Ni = 3.89/58.6934g
Number of atoms of Ni = 
Number of atoms of Ni = 0.39 X 10²³
Mass of silver, Ag = 6.61g
Molecular weight of Ag = 107.8682g
Number of moles of Ag = 6.61/107.8682
Number of atoms of Ag = 
Number of atoms of Ag = 0.36 X 10²³
Therefore, Nickel contains for atoms.
Answer:
Approximately 53.3 %.
Explanation:
Molar mass of C2H4O2
= 2 * 12.011 + 4 * 1.008 + 2 * 15.999
= 60.052
% oxygen = (31.998* 100) / 60.052 = 53.28 %
