Answer:
B)
Explanation:
The layers of the atmosphere are classified by changes in temperature in accordance with height.
Answer:
1.51×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Calcium (Ca = 10 g
Number of atom of Calcium (Ca) =?
The number of atoms present in 10 g of Ca be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole Ca contains 6.02×10²³ atoms.
1 mole of Ca = 40 g.
Now, if 40 g of Ca contains 6.02×10²³ atoms.
Therefore, 10 g of Ca will contain = (10 × 6.02×10²³) / 40 = 1.51×10²³ atoms.
Thus, 10 g of calcium contains 1.51×10²³ atoms.
Answer:
Molecules in both the metal and the surrounding air will start moving at higher speeds.
Explanation:
Temperature is a measure of the average kinetic energy of the molecules in a body. Thus, as the temperature of a body increases, its molecules tend to move faster.
At a high temperature of 150°C, the molecules in the metal hot plate move faster. Similarly, this heat is also transferred to the surrounding air molecules and they too start moving faster.
Therefore at 150°C, molecules in both the metal and the surrounding air will start moving at higher speeds.
Why does a straw look bent in a glass of water?
Answer:
Refraction
Explanation:
A straw looks bent in a glass of water due to the refraction of light as it crosses the air - water boundary.
Refraction is the bending of light rays as it crosses the boundary of one medium to another. The density differences between the medium will determine how the light ray will bend.
- Water is denser than air.
- The image formed to the eyes will be a refracted or bend ray convergent.