First, let's count mole of 10 g Calcium Carbonate
mole = Mass / Molecular Mass
Calcium Carbonate = CaCO₃
Molecular Mass = Ar Ca + Ar C + (3 x Ar O)
Molecular Mass = 40 + 12 + (3 x 16)
Molecular Mass = 100
next
Mole of CaCO₃ = 10 gram / 100
Mole of CaCO₃ = 0,1 mol
then equal the reaction equation first
CaCO₃ + 2 HCl ==> CaCl₂ + CO₂ + H₂O (Equal)
To count the mass of carbon dioxide that produced we must know the mole of CO₂ first
we can count by coefficient comparison
mole CO₂ = 
x mole CaCO₃
mole CO₂ = (1/1) x 0,1 mole
mole CO₂ = 0,1 mole
so
Mass of CO₂ = mole CO₂ x Molecular Mass of CO₂
Mass of CO₂ = 0,1 mole x (12 + (2 x 16))
Mass of CO₂ = 0,1 mole x 44
Mass of CO₂ = 4,4 g
so, mass of carbon dioxide that's produced by 10 g of calcium carbonate on reaction with chloride acid is 4,4 g.
This is the order of activity in decreasing way for the mentioned metals
Mn>Zn>Cr>Fe>Cd>Co>Ni>Pb
Fe is in between Cr and Cd, it is more active than Cd and less active than Cr, so it will displace Cd but not Cr.
Answer:Fe (it will displace Cd, but not Cr)
Answer:
it will decrease the speed
Answer:
Explanation:
also known as hydronium ion is formed as a result of the reaction between an hydrogen proton and a water molecules.
i.e 
(molecular geometry for the hydronium ion shows that the lewis structure of hydronium ion possess a three hydrogen ion bonded to a central atom known as oxygen. The oxygen possess a lone pair with a positive ion. So we have three hydrogen atoms and a lone pair attached to the oxygen. We can now say that there are four groups as the steric number in which one of them is a lone pair. This give rise to the trigonal pyramidal shape of the (hydronium ion) with a bond angle of about 109,5°
Similarly, 
on the other hand also known as ammonia has a shape that can be also determined by the Lewis structure.
IN ammonia, there are three hydrogen and a lone pairs of electron spreading out as far away from each other from the centre nitrogen. In essence, the valence shell electron pair around hydrogens tend to repel each other. Hence, giving it a trigonal pyramidal shape.
From above the similarities between H3O and NH3 is in their molecular geometry in which both H3O and NH3 have the same shape.
These molecules are called isoelectronic. Why?
Isoelectronic molecules are molecules having the same number of electrons and same electronic configuration structure. As a result H3O and NH3 possess the same number of electrons in the same orbitals and they also posses the same structure.
