Answer:
The Symbols of elements is given by :
IUPAC : International Union Of Pure and Applied Chemistry .
Its is the Universally recognuised organisation which works on Chemical nomenclature and terminology.
Explanation:
According to IUPAC the elements are named according to mythological concept of country ,mineral , place , property and scientist.
Ex:Copper name comes from the old english word Cyprus.
Rules of Naming elements :
1. The first Alphabet of the element is always Capital.Example:-
Sodium : Na not ''na'
2. The second alphabet is always small .Example
Sodium : Na not ''nA' or NA
3.For most of the elements ,The symbol of the element comes from the <u>first two words.</u>
Example : Hydrogen : H
Helium : He
Copper : Cu
Rules for naming elements having mass> 100
1. The names are derived directly from the atomic number .
Ex : 0 = nil 1= un 2=bi 3=tri
2. The name always ends with ''ium''
For example :
102 = Unnilbium
We can assume that all<span> gravitational potential energy is converted into
kinetic energy of the object.</span><span>
<span>Hence, </span>GPE = KE
Where GPE is gravitational Potential Energy (J)
and KE is Kinetic Energy (J)
GPE = mgh
<span>Where, m is the mass of the object (kg), g is acceleration due to gravity (9.8 m s</span></span>⁻<span>²) and h is the height to the<span> object from ground (m).</span></span><span>
m = 0.18 kg
g = 9.8 m s</span>⁻²<span>
h = 45 m
Hence,
GPE = 0.18 kg x 9.8 m s</span>⁻² x 45 m<span>
= 79.38 J
≈ 79 J
<span>Hence, </span>KE = GPE = 79 J
<span>Hence, the
answer is '79 joules'.</span></span>
Answer:
250 mmol are left after 26.60 secs ≅ 26.6 seconds
Explanation:
zero order kinetics formula is:
[A] = [A₀] - kt
where [A] = amount left; [A₀] = amount remaining; k = rate constant; t = time
concentration [A₀] = mole/volume = 0.5 mole/2.0L = 0.25
[A] = 0.25 mole/2.0L = 0.125 M
k = 0.0047 Ms⁻¹
t = {[A]-[A₀]}/-k = (0.125 - 0.25)/(-0.0047) = 26.60 seconds = 26.6 seconds
the amount is reduced by half after 26.6 seconds
CaI₂ + Hg(NO₃)₂ --------->HgI₂ + Ca(NO3)2
2Al + 3Cl₂ --------->2AlCl3
Ag + HCl ------->AgCl + H2
C2H2 + 5O2 --------> 4CO2 + 2H2O
MgCl₂ --------->Mg + Cl2
It comes to from the chemical reaction itself. Exothermic reaction release heat because the energy level of the products is lower than that of the reactants. Therefore, the net enthalpy change of the reaction is negative (-), meaning heat or light (or any other form of energy) is released into the environment. An example of an exothermic reaction is the combustion of fuel.
