Answer:
D. It is the sharing of electrons between atoms with an electronegativity difference below 1.7
Covalent bonds share electrons, whereas ionic bonds exchange electrons. Covalent bonds have an electronegativity of 0.0-1.7 (0.0-0.3 is a nonpolar covalent bond and 0.3-1.7 is a polar covalent bond). Ionic bonds are bonds that go beyond the electronegativity of 1.7 to 4.0 (1.7-4.0).
If the half-life of a sample of a radioactive substance is 30 seconds, how much would be left after 60 seconds? <span>
A. one-fourth</span>
<span>7.379 * 10^(-4) is measured, hence prone to error, either human error or via measuring device. In this case,
100 cm = 1 m is written in stone and is unquestionable.
The density of the gold is 19.3 g/cm^3 and could be an approximation.
The approximation is good to at least one night.</span>
Answer:
D. It is a chemical reaction because the total mass remains the same when new substances are formed.
Explanation:
A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.
For example:
6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂
it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen. The number of atoms are same on both side however arrangement of atoms is different.
While in case of nuclear reaction small change in mass take place.
If you have a book, read it!! I promise you, it tells you this answer!
