Answer:
mass of Helium = mole of Helium x Molarmass of Helium
Explanation:
Mole of Helium = volume of Helium/ 22.4dm^3/mol
= 7.00 x 10^2/22.4
= 31.25mol
Mass of Helium = mole of Helium x Molarmass of Helium
= 31.25mol x 4g/mol
= 125g
Answer:
The number of valence electrons can be known from the group that the element is in (except the lanthanides, actinides and groups 3-12).
Explanation:
Group 1 has 1 valence electron. Group 2 has 2 valence electrons. Group 13 has 3 valence electrons. Group 14 has 4, group 15 has 5, group 16 has 6, group 17 has 7, and group 18 has 8.
Group 18 are the noble gases which are stable.
Group 17 are the halogens and react well with the alkali metals.
There are many forms of energy: like solar, wind, wave and thermal to name a few, but the 6 Forms of Energy we study in Needham are: Sound, Chemical, Radiant, Electric, Atomic and Mechanical. Sound Energy- is produced when an object is made to vibrate. Sound energy travels out as waves in all directions.
Answer: enthalpy of reaction.
Explanation:
Temperature of the gas is defined as the degree of hotness or coldness of a body. It is expressed in units like 
and 
Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.
Free energy is the amount of energy that can be converted into useful work.
Enthalpy of the reaction is the difference between the energy of products and the energy of reactants. it is either the heat released or absorbed during the reaction. It is either positive or negative.
