An atom that has 13 protons and 15 neutrons is isotope of Aluminium (answer C)
<u><em>Explanation</em></u>
- Isotope is a form of the same element with the equal number of protons but difference number of neutrons in their nuclei.
- In other words isotope has the same atomic number but different mass number.
- Atomic number of a element is determined by number of protons of an element.
- from the periodic table Aluminum in atomic number 13 therefore it has 13 protons <em>therefore an atom that has 13 protons and 15 neutrons is a isotope of Aluminium. </em>
There are 76 atoms in total
1.34 moles are in 135g of Teflon.
Explanation:
Molecular formula of teflon is (C2H4)n
mass of teflon = 135 grams
atomic mass of teflon = 100.01 gram/mole
number of moles of teflon = ?
Formula used to calculate number of moles in a substance is given as:
number of moles = 
putting the values in the above equation:
number of moles = 
number of moles = 1.34 moles
Teflon is polymer which is used for making non-stick coating, in 135 grams of teflon there are 1.34 moles in it.
Example:
sample density of gasoline, 20 g of weigth into 5 <span>mL
Answer:
D = m / V
D = 20 g / 5 mL
D = 4 g/mL</span>