Answer:
One mole of oxygen atoms has a mass of 16 g, as 16 is the atomic weight of oxygen, and contains 6.02 X 10^23 atoms of oxygen.
Explanation:
Answer:
6.02 × 10²³ atoms
Explanation:
The number 6.02 × 10²³ is called Avogadro number. It is the number of atoms, ions and molecules in one gram atoms of an element, one gram ions of substance and one gram molecule of a compound.
For example:
32 g of oxygen = one mole = 6.02 × 10²³ atoms O.
1.008 g of hydrogen = one mole = 6.02 × 10²³ atoms of H.
or
18 g of H₂O =one mole = 6.02 × 10²³ molecules of H₂O
44 g of CO₂ = one mole = 6.02 × 10²³ molecules of CO₂
or
62 g of NO₃⁻ = one mole of NO₃⁻ = 6.02 × 10²³ ions of NO₃⁻
<h3><u>Answer;</u></h3>
<em>D. Have different structures and different functions</em>
A plasma membrane and a cell wall <em><u>have different structures and different functions</u></em>.
<h3><u>Explanation;</u></h3>
- <em><u>Plasma membrane</u></em> is a structure that is found in <u><em>both animal cell and plants cells</em></u>. It is made up of a <u><em>bi-layer consisting of lipid and proteins</em></u>. Plasma membrane are semi-permeable which means the<em><u> allow selective movement of materials in and out of the cell. </u></em>
- <em><u>Cell wall</u></em>, on the other hand is a structure that is found on plant cells and lacks in animal cell. It <em><u>contains cellulose in its structure </u></em>which enables it to be rigid and enhances it <em><u>protect the cell from mechanical damage</u></em> from harsh conditions such as pressure in the outside environment.
For the first question, the correct answer among the choices listed is option A, a chocolate bar melting in hot car. It is an endothermic process because it absorbs heat energy for it to be melted. For the second question, it think the correct answer is the last option, <span>(-2222) + (-1182) - (-1144).</span>
