They are a relatively recent invention.
I hope it was helpful for you.
Answer:

Explanation:
= Mass of metal = 19 g
= Specific heat of the metal
= Temperature difference of the metal = 
V = Volume of water = 150 mL = 
= Density of water = 
= Specific heat of the water = 4.186 J/g°C
= Temperature difference of the water = 
Mass of water

Heat lost will be equal to the heat gained so we get

The specific heat of the metal is
.
Sodium is a metal, Chloride is a non-metal.
Right off the bat, you know that in order for both of these atoms to achieve a full valence shell that the metal has to lose electrons, and the non-metal has to gain them.
Therefore, you have the transfer of electrons in this bond in order to form ions.
Na+ and Cl-. This transfer of electrons in a bond is called an {{ Ionic Bond}}
On June 21, as seen from the North pole ...
-- the sun has been up, and it's been light outside,
for the past three months ... ever since March 21 .
-- The sun won't set, and it won't be dark outside,
for another three months ... until September 21.
-- Here at the North pole, it stays daylight for six months straight.
Today, on June 21, we're exactly halfway through the period of
continuous daylight.
Answer: The empirical formula for C6H12O6 is CH2O. Every carbohydrate, be it simple or complex, has an empirical formula CH2O
Explanation: