Answer:
91.7 kJ
Explanation:
Step 1: Given data
- Mass of ammonia (m): 66.7 g
- Molar heat of vaporization of ammonia (ΔH°vap): 23.4 kJ/mol
Step 2: Calculate the moles (n) corresponding to 66.7 g of ammonia
The molar mass of ammonia is 17.03 g/mol.
66.7 g × 1 mol/17.03 g = 3.92 mol
Step 3: Calculate the heat (Q) required to boil 3.92 moles of ammonia
We will use the following expression.
Q = ΔH°vap × n
Q = 23.4 kJ/mol × 3.92 mol = 91.7 kJ
Answer is: nickel (Ni) is the most active metal.
Chemical reaction 1: Pb(NO₃)₂(aq) + Ni(s) → Ni(NO₃)₂(aq) + Pb(s).
Chemical reaction 2: Pb(NO₃)₂(aq) + Ag(s) → no reaction.
Chemical reaction 3: Cu(NO₃)₂(aq)) + Ni(s) → Ni(NO₃)₂(aq) + Cu(s).
From chemical reactions 1 and 3, we can conclude that nickel is more reactive than lead (Pb) and copper (Cu), because lead is more reactive than silver (Ag), chemical reaction 2, nickel is also more reactive than silver.
In chemical reaction 2, no reaction occurs because silver is less reactive than lead. Lead is higher in activity series of metals and can not be reduced.
Nickel is higher in activity series of metals than lead, copper and silver.
The activity series is a series of metals from highest to lowest reactivity. Metal higher in the reactivity series will displace another.
Answer/Explanation:
We cannot see the passage, but SAD stands for Seasonal Affective Disorder. SAD is a type of depressive disorder related to lack of light, and therefore changes with the seasons. It is a severe version of the "winter blues"
In the winter months, where the days are shorter, individuals who suffer from SAD suffer from mood changes. They get depressed, have a reduction in energy levels, and withdraw socially. They may also gain weight. This causes problems with relationships, work, and school.
Since SAD is linked to light, SAD is likely more common in the Northern areas of the United States, where winter days are shorter.
use a mortar & pestle to grind the solute into smaller particles, thus increasing the surface area.
