44.8% oxygen, 21.5% silicon, and 22.8% magnesium. There's also iron, aluminum, calcium, sodium, and potassium. These elements are all bound together in the form of silicate rocks, all of which take the form of oxides.
Plastic building blocks are good for building molecules because of some useful properties which they possess. For instance, plastic are flexible, they can be easily manipulated and can be made into any shape, size and combination. They can also be produced using different colors. Because of these features, they can be used to build and to explain how molecules behave.
Amount of oxygen in the compound = 160 g
Amount of oxygen in the compound = 20.2 gm
Mole of oxygen in the compound = 160/16
= 10 moles
Mole of hydrogen in the compound = 20.2/1.01
= 20 moles
Then
The ratio of oxygen to ration of hydrogen = 1:2
So
The empirical formula of the compound is H2O. I hope the answer has come to your help.
Question 17:
False; cutting hair would change what it looks like but, braiding it keeps it the same substance it is.
Question 18 :
My best guess would either be A or D. I would lean more towards D because if there are different mixtures then it depends on what you are mixing.
Hope it helps in some way. <3
The balanced equation for the reaction between Mg and HCl is as follows
Mg + 2HCl --> MgCl₂ + H₂
stoichiometry of HCl to H₂ is 2:1
number of HCl moles reacted - 0.400 mol/L x 0.100 L = 0.04 mol of HCl
since Mg is in excess HCl is the limiting reactant
number of H₂ moles formed - 0.04/2 = 0.02 mol of H₂
we can use ideal gas law equation to find the volume of H₂
PV = nRT
where
P - pressure - 1 atm x 101 325 Pa/atm = 101 325 Pa
V - volume
n - number of moles - 0.02 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature in Kelvin - 0 °C + 273 = 273 K
substituting these values in the equation
101 325 Pa x V = 0.02 mol x 8.314 Jmol⁻¹K⁻¹ x 273 K
V = 448 x 10⁻⁶ m³
V = 448 mL
therefore answer is
c. 448 mL
