O2.
Because it is only made up of one type of element it is an element. Howevern there is more than one oxygen atom because oxygen cannot exist as a single atom, therefore making it a molecule as well.
The lowest <span>temperature is the coldest. </span>
Answer:
The argument about the chemical and physical changes in the energy is correct.
This is so because when a log is burnt, the chemical change occurs as wood releases energy in the form of carbon dioxide are formed which is irreversible while the changes in energy of movement of the pendulum is a physical change as its potential energy converts to kinetic and kinetic energy again converts to the potential which is a reversible process.
Hence, the argument saying the changes in energy occurring on a pendulum and log is right.
Answer:
d = 11400 kg/m³
Explanation:
The density of lead is 11.4 g/cm³
We need to convert the density in kg/m³ in scientific notation.
We know that,
1 kg = 1000 g
1 cm = (1/100) m = 0.01 m
Density,
So, the density of the lead is 11400 kg/m³.
Answer:
Option D = No, when elements combine to form a new material, they have properties unique to the new materials.
Explanation:
When sodium contact with water it loses its one electron and thus gain positive charge. When there are more sodium atoms present and many atoms do this thus more positive ions are produced and these positive ions repeal each other at high speed and explosion occur.
But when it form compound with other material, it will not showed this behavior.
Example:
Consider the sodium chloride, when it dissolve in water sodium not showed explosion. In sodium chloride sodium already gives its electron to the chlorine and have stable electronic configuration. The sodium present in cationic form. When it dissolve, partial positive charge of water surrounds the Cl⁻ and partial negative charge of water surrounds the Na⁺ ion, ans sodium chloride gets dissolve into water without explosion.
