JJ Thomson discovered electrons using the cathode ray. Electrons are negatively charged particles that orbit around the nucleus of an atom. Finding out that there was a negative charge to balance out the positive charge. This later helped develop Hund's Rule and the Pauli Exclusion Principle.
In the choices above, the correct letter of the question is letter a, scintillation counter. It is because it uses a phosphor-coated surface in order to use its function in detecting radiation. Its component could produce bright flashes where it will be sufficient in detecting the radiation.
Answer:
$200.0 is the cost for installing a carpet for a room that measures 12.0 feet by 15.0 feet.
Explanation:
Length of the room = l = 15.0 ft =
Width of the room = w = 12.0 ft =
(1 yard = 3 feet)
Area of the room = l × w =
Cost for installing a carpet for a room = $10 per square yard
Cost for installing a carpet for a room wit area 20.0 square yard :
$200.0 is the cost for installing a carpet for a room that measures 12.0 feet by 15.0 feet.
Answer:
2.4 moles of oxygen are needed to react with 87 g of aluminium.
Explanation:
Chemical equation:
4Al(s) + 3O₂(l) → 2AlO₃(s)
Given data:
Mass of aluminium = 87 g
Moles of oxygen needed = ?
Solution:
Moles of aluminium:
Number of moles of aluminium= Mass/ molar mass
Number of moles of aluminium= 87 g/ 27 g/mol
Number of moles of aluminium= 3.2 mol
Now we will compare the moles of aluminium with oxygen.
Al : O₂
4 : 3
3.2 : 3/4×3.2 = 2.4 mol
2.4 moles of oxygen are needed to react with 87 g of aluminium.