Answer:
As a substance melts, and goes from a solid to a liquid state, the kinetic energy of the molecules increases, and the molecules move faster, and they separate further and further away from each other. The intermolecluar forces holding the molecules together become weaker. This is why a liquid can take fill the shape of its container, whereas a solid has a fixed shape.
Explanation:
take your notes man
Answer:
Single Replacement; 2, 1, 1, 1
Explanation:
2HCl + Zn → H2 + ZnCl2
In a single replacement reaction, one specie is replaced by another specie in a chemical reaction.
If we look at the reaction above, zinc metal reacted with hydrochloric acid. The reaction proceeds in such a manner that zinc replaces hydrogen in hydrochloric acid. This is a single replacement reaction because only one chemical specie is displaced in the reaction.
Answer:
3.75 moles
Explanation:
The chemical equation is 2CH₃OH + 3O₂ -> 2CO₂ + 4H₂O
2 moles of CH₃OH are burned by 3 moles of O₂
For 2.5 moles of CH₃OH are burned by x moles of O₂
Let's solve for x :
2*x=2.5*3 => 2*x=7.5 => x=3.75 moles of O₂ are needed to burn 2.5 moles of CH₃OH
Answer:
True.
Explanation:
There are three ways to make a buffer.
a. Generating a solution of a weak acid and its conjugate base.
b. Adding to a solution of a weak acid a certain quantity of
strong base, so that the acid remains in excess.
c. adding a limited amount to a conjugate base solution
of strong acid so that the base remains in excess.
We are in c, in this situation.
How do you calculate, pH? We apply Henderson Hasselbach.
pH = pka + log (mmoles base - mmoles acid)/ mmoles acid
pH = pKa + log ((20 ml . 1 M - 1 ml . 10M) / 10 mmoles
pH = 4.76 + log 1 → 4.76 ⇒ pH = pKa
