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
The difference in
hardness between diamond and graphite is that diamond has an ordered
arrangement of atoms within its structure that makes it harder and stronger
than graphite. This is due to the high pressure and high temperature that it
went.
Answer:
7.7439×10⁻³¹ m
Explanation:
The expression for Heisenberg uncertainty principle is:
Where m is the mass of the microscopic particle
h is the Planks constant
Δx is the uncertainty in the position
Δv is the uncertainty in the velocity
Given:
mass = 0.68 g = 0.68×10⁻³ kg
Δv = 0.1 m/s
Δx= ?
Applying the above formula as:
<u>Δx = 7.7439×10⁻³¹ m</u>
<h3><u>Answer;</u></h3>
When hydrogen is covalently bonded to an electronegative atom
<h3><u>Explanation;</u></h3>
- Hydrogen bonding is a special type of dipole-dipole attraction between molecules. It results from the attractive force between a hydrogen atom covalently bonded to a very electronegative atom such as a N, O, or F atom.
- Highly electronegative atoms attract shared electrons more strongly than hydrogen does, resulting in a slight positive charge on the hydrogen atom. The slightly positive hydrogen atom is then attracted to another electronegative atom, forming a hydrogen bond.
Answer:
Beryllium, because it is in period 2 and has four total electrons.
Explanation:
