Answer : C
Explanation:
a star produces energy by combining two atoms into one creates a powerful burst of energy
Answer:
Option B is the most correct.
If a system loses energy to the surroundings, then the surroundings must do an equal amount of work on the system. if the surroundings gain energy from the system, then the system must lose an equal amount of energy.
Explanation:
The first law of thermodynamics is the law of conservation of energy. It explains that energy can neither be created nor destroyed, but can only be transformed from one form to another of transferred from one place to another (In various forms at times).
So, if a system gains energy from the surroundings, it is evident that this energy wasn't created, it was transferred in from the surroundings, meaning that the surroundings have lost that same amount of energy and vice versa.
So, it is obvious why option B is the most correct of all the options.
Hope this Helps!!!
initial condition : Vi = 4.700 L , Ti = 71.0ºC +273 => 344 K
final condition : Vf = 3.300 L , Tf = ?
Pressure is constant:
According to charle's law , volume is directly proportional to temperature at constant pressure !
Hence Vi / Ti = Vf / Tf
4.700 L / 344 K = 3.300 L / Tf
Tf = 3.300 L * 344 K / 4.700 L
Tf = 1135200 / 4.700
Tf = 241.53 K
Tf = 241.53 - 273
Tf = -31.47ºC
Answer: B. It’s a dilute strong base.
Explanation:
1) Definition of acids and bases: as per Bronsted-Lowry model, an acid is a substance that donates hydrogen ions and a base is a substance that accepts hydrogen ions.
Ca(OH)₂ does not have hydrogen ions to donate, but it can accept hydrogen ions to form H₂O according to this equation: H⁺ + OH⁻ → H₂O.
Hence, Ca(OH)₂ is a base.
2) Definition of strong base: a strong base is a base that dissociates completely into metallic and hydroxide ions in aqueous solutions, while a weak base dissociates partially.
Hence, Ca(OH)₂ is a strong base.
3) Definition of dilute: it refers to a solution meaning that the substance is not pure and the concentration is low. Since, the solution the Ca(OH)₂ is 0.02 M means that it is dilute.
Therefore, we have found that the description of 0.02 M Ca(OH)₂ is that is is a dilute strong base (option B).
Answer:
Reactants
Explanation:
The substance (or substances) initially involved in a chemical reaction are called reactants or reagents.