30grams
Explanation:
If a reaction starts with 30grams then the reaction should end with 30grams.
This in conformity with the law of conservation of mass.
- The law states that "in an isolated system, mass is neither created nor destroyed during chemical transformation".
- Mass is the quantity of matter contained in a substance.
- In chemical reactions, the mass of reactants must always be the same with the mass of the product baring any loss.
- In an isolated system, there is no exchange of energy and mass.
- Chemical systems are usually treated as isolated systems in which mass is conserved.
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Chemical laws brainly.com/question/5896850
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Answer: A. Work is done on the system and heat is transferred from the system for a net decrease in internal energy.
Explanation:
A refrigerator is a device which dispenses heat from the close system to a warmer area or in the surrounding. By dispensing the heat the internal temperature of the refrigerator drops. The system of refrigerator violates the second law of thermodynamics. As it performs the work to cool the region instead of heating the region. The work is done on the system and the internal energy decreases and the heat energy is liberated to the surrounding area. A refrigerator is an open system.
A higher frequency. I just got this answer on usa test prep.
Answer:
E. Zero Maximum
Explanation:
At the point of maximum displacement, the speed is zero while the restoring force is maximum. In fact:
- The restoring force is given by 
, where k is the spring constant and x is the displacement - at the point of maximum displacement, x is maximum, so F is maximum as well
- the total energy of the system is sum of kinetic energy and elastic potential energy:
where m is the mass of the system and v is the speed. Since E (the total energy) is constant due to the law of conservation of energy, we have that when K increases, U decreases, and viceversa. As a result, when x increases, v decreases, and viceversa. At the point of maximum displacement, x is maximum, so v will have its minimum value (which is zero, since the system is changing direction of motion).
