Answer:
b. oxygen side being slightly negative and the hydrogen side being slightly positive.
Explanation:
The water molecule is a polar molecule, that is to say that its distribution of electronic density is different throughout the molecule.
In this way, in the water molecule there is a negative partial charge towards the oxygen atom and a positive partial charge towards the hydrogen atom.
This polar characteristic of the water molecule allows ions and other molecules to exhibit water solubility and is widely used in chemical reactions.
Boron can be combined both with metallic elements as nonmetallic to Covalent compounds forming, since in no case give rise to Ionic States, cations (positively charged ions) or anions (negatively charged ions).
hope this helps!
Color change
new substance formed
heat or light change
new smell
irreversible
Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M
Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M
I would say it is a chemical change because after a while, the nails start to rust. Now they only rust after about a week though. But rust is a chemical change.
