A plateau is a flat, elevated landform that rises sharply above the surrounding area on at least one side. Plateaus occur on every continent and take up a third of the Earths land. They are one of the four major landforms, along with mountains, plains, and hills.
1.59moles
Explanation:
Mass of CaO = 89.23g
Unknown
Number of moles = ?
Solution:
The mole is a unit of measurement in chemistry used to delineate the number of particles an atom contains.
A mole of a substance contains the avogadro's number of particles.
Number of moles = 
Molar mass of CaO = 40 + 16 = 56g/mol
Number of moles = 
= 1.59moles
learn more:
Number of moles brainly.com/question/1841136
#learnwithBrainly
The range in size of most atomic radii is approximately <span>5 × 10−21 m to 2 × 10−20 m. The rest of the choices do not answer the question above.</span>
Common sense tells me that it is asthma cause i have it and yeah good luck
1) mass composition
N: 30.45%
O: 69.55%
-----------
100.00%
2) molar composition
Divide each element by its atomic mass
N: 30.45 / 14.00 = 2.175 mol
O: 69.55 / 16.00 = 4.346875
4) Find the smallest molar proportion
Divide both by the smaller number
N: 2.175 / 2.175 = 1
O: 4.346875 / 2.175 = 1.999 = 2
5) Empirical formula: NO2
6) mass of the empirical formula
14.00 + 2 * 16.00 = 46.00 g
7) Find the number of moles of the gas using the equation pV = nRT
=> n = pV / RT = (775/760) atm * 0.389 l / (0.0821 atm*l /K*mol * 273.15K)
=> n = 0.01769 moles
8) Find molar mass
molar mass = mass in grams / number of moles = 1.63 g / 0.01769 mol = 92.14 g / mol
9) Find how many times the mass of the empirical formula is contained in the molar mass
92.14 / 46.00 = 2.00
10) Multiply the subscripts of the empirical formula by the number found in the previous step
=> N2O4
Answer: N2O4
