B. In the system of the object and the earth, by Newton's third law, the object will exert and equal and opposite force upon the earth.
Answer: chloroplast
Explanation:
The chloroplast are organelles that conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight
Answer:
The right option is (d) substance undergoing a change of state
Explanation:
Latent Heat: Latent heat is the heat required to change the state of a substance without change in temperature. Latent heat is also known as hidden heat because the heat is not visible. The unit is Joules (J).
Latent heat is divided into two:
⇒ Latent Heat of fusion
⇒ Latent Heat of vaporization.
Latent Heat of fusion: This is the heat energy required to convert a substance from its solid form to its liquid form without change in temperature. E.g (Ice) When ice is heated, its temperature rise steadily until a certain temperature is reached when the solid begins to melts.
Latent Heat of vaporization: This is the heat required to change a liquid substance to vapor without a change in temperature. The latent heat depend on the mass of the liquid and the nature of the liquid. E.g When water is heated from a known temperature its boiling point (100°C) When more heat is supplied to its boiling temperature, it continue to boil without a change in temperature.
From The above, Latent heat brings about a change of state of a substance at a steady temperature.
The right option is (d) substance undergoing a change of state
Answer:
- a change in color
- the formation of a precipitate
- the formation of bubbles
Explanation:
In a chemical reaction, there is always a rearrangement of atoms within the molecules of reactants to form new products. Such a change is different from changes in the physical form of molecules, e.g. shape.
Thus, according to this criteria, only three options are correct in the given question. A change in color is definitely an indication of chemical reaction because the emission of light before and after cannot be changed unless molecules are rearranged to form a new chemical. Likewise, precipitates form when a reaction takes place between chemically dissolved molecules to form less or not dissolvable compounds. In the end, the configuration of bubbles also indicates that the reaction has taken place because new gases are being released.
On the other hand, change in shape is a physical change because the composition doesn't need to also been changed. An example is the ice formation from water. Same is the case with "change of clear liquid to cloudy" because the addition of non-reactive substances could change the nature of liquid to cloudy however the reaction doesn't need to have taken place.
