Some common elements that are gaseous state at room temperature are:
Oxygen
Nitorgen
Fluorine
Chlorine
Hydrogen
Helium
In addition, all of the elements in group VIII are gases too, they have an octet of electrons (complete outer electron shell) , they're really stable and therefore they're called noble gases. Some examples from group VIII include helium, krypton, xenon etc.
Substance exist as gases in room temperature is due to their boiling point, where is it lower than the room temperature (usually around 25°C). If their boiling point is higher than room temperature, they should exist as either solid or liquid, which is how the majority of the elements in the periodic table is.
Answer:
30grams
Explanation:
To calculate the mass (number of grams of the solute) in the solution, we need to calculate the number of moles it contains first. We use the formula;
M = n÷ V
Where; M= Molarity or Molar concentration = 2.055M
n= number of moles= ?
V= Volume = 250mL
Volume in L is 250/1000 = 0.250L
n= M × V
n= 2.055 × 0.250
n= 0.51375moles
The mass is calculated using :
Mole (n) = mass (m) / molar mass (MM)
Molar mass of NaCl = 23 + 35.5
= 58.5g/mol
Mass = molar mass × mole
Mass = 58.5 × 0.51375
Mass = 30.0543
Therefore, the mass is 30grams
Precambrian. Precambrian Oldest and longest era of Earth's history, lasting from the formation of the Earth c.4.6 billion years ago<span> to the beginning of a good fossil record c.</span>590 million years ago<span>.</span>
