Answer:
0.1688L of the 1M NaOH stock solution
Explanation:
A 215mM = 0.215M solution of NaOH contains 0.215 moles per liter. As you want to prepare 785mL = 0.785L of the 0.215M you will need:
0.785L × ( 0.215mol / L) = 0.1688 moles of NaOH.
<em>These moles of NaOH comes from the 1M stock solution</em>, that means the volume of 1M NaOH solution you need is:
0.1688 moles NaOH × (1L / 1mol) =
<h3>0.1688L of the 1M NaOH stock solution</h3>
Answer:
Ionic bond
Explanation:
An ionic bond holds positive and negative ions together.
Answer:
a. +2
b. +3
c. -1
Explanation:
The typical oxidation states can be determined from the periodic table based on the number of valence electrons an atom has.
a. Calcium belongs to group 2A, meaning it has 2 valence electrons and, therefore, would have an oxidation state of +2 in compounds.
b. Aluminum is in group 3A, meaning it has 3 valence electrons and would have an oxidation state of +3 in compounds when the 3 electrons are lost.
c. Fluorine would become fluorine if it gained 1 additional electron to achieve an octet, so its oxidation state would be -1.
Answer:
–500KJ
Explanation:
Data obtained from the question include the following:
Heat of reactant (Hr) = 800KJ
Heat of product (Hp) = 300KJ
Enthalphy change (ΔH) =..?
The enthalphy change is simply defined as the difference between the heat of product and the heat of reactant i.e
Enthalphy change = Heat of product – Heat of reactant
ΔH = Hp – Hr
With the above formula, we can easily calculate the enthalphy change as follow
ΔH = Hp – Hr
ΔH = 300 – 800
ΔH = –500KJ.
Therefore, the overall energy change for the reaction between hydrogen and oxygen shown in the diagram above is –500KJ