The answer is 2 pairs. The carbon atom has 4 electrons and oxygen atom has 6 electrons. The purpose of shared electron is to get 8 electrons at the outer layer. So the carbon atom needs to share 4 electrons which is 2 pairs with oxygen to be stable.
A. solutions and colloids
All of them are properties of compounds except III.
for I, compounds are chemically combined together, so to separate them, we must use chemical methods like electrolysis or applying heat. These requires large amount of energy.
For II, they're always fixed. For example, in water (H2O), the ratio of hydrogen and oxygen is always 1:8 in mass. If there's some extra added, the substance becomes mixture instead of compounds.
For IV, after you chemically combined elements or compounds together, their properties are completely different. For example, iron can be attracted to magnets, but iron II sulphide does not.
The balance chemical equation is :
2HCL + Na2CO3 -----> 2NaCl + H2O + CO2
According to Question,
Given,
Molarity of HCL = 1.75 m
Sodium Carbonate (Na2CO3) = 0.100 m
For finding out the molarity,
c = n solute / Vsolution => n = c.Vsolution
nCO^2-3 = 0.100 mol L^-1 . 0.750 L = 0.0750 moles of CO^2-3
0.0750 moles of CO^2-3 . 2 moles H3O^+ / 1 mole CO^2-3
= 0.150 moles of H3O^+
As we have already know the molarity of HCL , we easily calculate what volumes by many moles.
c = nsolute / Vsolution => Vsolution = nsolute / c
VH3O^+ = 0.150 moles / 1.75 mol L^-1 = 0.0857 L
To know more about Molarity here :
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Answer: -
0.2 Kg
Explanation: -
The equation used by Rhia for the carbon footprint measurement is
C = 0.2 B + 0.1 S
where S miles are by subway, B miles by bus and C is Kg of carbon dioxide.
From the equation we see the coefficient of B is 0.2.
Thus 0.2 Kg of carbon dioxide per mile the bus portion contributes to Rhia's carbon footprint.