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⁻
Melting ice cream is a physical change because it is a phase change, the water in the ice cream gains thermal energy and the inter-molecular forces are overcome and the molecules move further apart forming a liquid. It is not a chemical change because no chemical reactions occurred.
Abbreviation. DNA, which stands for deoxyribonucleic acid, is defined as a nucleic acid that contains the genetic code.
Answer:
Chemical change.
Explanation:
When it is heated it decomposes into mercury and oxygen gas. The mercury oxide reactant becomes the silver color of mercury. Hence, a color change can be noticed throughout the reaction.
