Answer: There are 
atoms of hydrogen are present in 40g of urea, 
.
Explanation:
Given: Mass of urea = 40 g
Number of moles is the mass of substance divided by its molar mass.
First, moles of urea (molar mass = 60 g/mol) are calculated as follows.
According to the mole concept, 1 mole of every substance contains 
atoms.
So, the number of atoms present in 0.67 moles are as follows.
In a molecule of urea there are 4 hydrogen atoms. Hence, number of hydrogen atoms present in 40 g of urea is as follows.
Thus, we can conclude that there are atoms of hydrogen are present in 40g of urea, .
C. An atom of helium has its valence electrons in its first energy level, it wouldn't and can't satisfy the Octet rule as it only has 2 electrons, but with 2, it has a full shell, as the first energy level can hold only 2 electrons.
Answer:
False
Explanation:
The temperature at which a solid melts, known as its melting point is highly characteristic of a compound and element.
The melting point of pure substances, compounds and elements is definite and not varied.
- Melting point is an intensive property of matter.
- It does not depend on the amount of matter present.
- It is an innate or intrinsic property of every matter.
- For example, no matter the volume or mass of water, it will always boil at 100°C, all things being equal.
Therefore, melting point of most solids is characteristic of compounds and elements.
My guess would be "B) they were produced by volcanoes" because hawaii has a bunch of volcanoes and volcanoes can produce extra land. While the other answers wouldn't make sense. Definitely B.
Answer:
Osmosis is a type of passive transport. The best statement that accurately describes osmosis is: Osmosis is the diffusion of water across a membrane.
Explanation:
