Answer:
Q = 306 kJ
Explanation:
Given that,
Mass, m = 60 kg
Specific heat, c = 1020 J/kg°C
The temperature changes from 20°C to 25°C.
Let Q be the change in thermal energy. The formula for the heat released is given by :

Put all the values,

So, 306 kJ is the change in thermal energy.
Answer:
Calcium would displace barium.
Explanation:
Ba(NO₃)₂ + Ca --> Ca(NO₃)₂ + Ba
There are two types of compounds: molecular/covalent and ionic.
Molecular/covalent compounds are non-metal + non-metal.
Ionic compounds are metal + non-metal.
Looking at the periodic table, barium is a metal. Calcium is also a metal.
Checking a polyatomic ions chart would tell you NO₃⁻ is a non-metal because it has a negative charge.
Since there is no metal + metal compound, the calcium metal would displace barium. The compound remains ionic.
Is bubble chamber one of your choices? Bubble chamber sounds like a good fit for the question.
Answer:
Solid metal
Explanation:
The reduced form of metal ions is the metal in elemental state (simple substance). So, if you have a solution with metal ions and they are reduced, you probably will see the deposition of the metal. For example: if you have a solution with sodium ions (Na⁺), and the ions are then reduced, you will see the aparition of a solid phase of metallic sodium (Na(s)), according to the following half-reaction:
Na⁺ + e- → Na(s)