Answer:
1. Density of metal object = <em><u>11000 kg / m3</u></em>.
2. Could the object be gold = <em><u>No,because the density of gold is 19300 kg / m3</u></em>.
Hmmm, I believe the answer is "Exchange of energy with the surroundings"
Answer:- 14.0 moles of hydrogen present in 2.00 moles of
.
Solution:- We have been given with 2.00 moles of
and asked to calculate the grams of hydrogen present in it. It's a two step conversion problem. In first step we convert the moles of the compound to moles of hydrogen as one mol of the compound contains 7 moles of hydrogen. In next step the moles are converted to grams on multiplying the moles by atomic mass of H. The calculations are shown as:

= 14.0 g H
So, there are 14.0 g of hydrogen in 2.00 moles of
.
Answer:
The arrangement of the periodic table leads us to visualize certain trends among the atoms.
Elements are arranged from left to right and top to bottom in order of increasing atomic number.
The vertical columns (groups) of the periodic table are arranged so that all its elements have the same number of valence electrons (outer ring). All elements within a certain group share similar properties.
The rows are called periods. All elements in a row have the same number of electron shells.