Answer;
(3) Substance A is an element and substance Z is a compound.
Explanation;
-A compound is a substance formed when two or more chemical elements are chemically bonded together, such as water, carbon dioxide, methane, etc while an element is a pure chemical substance made of same type of atoms, such includes, oxygen, potassium, hydrogen, carbon, etc.
- Compounds can be broken
down or decomposed into simpler substances: elements cannot be broken down chemically into simpler substances .
Answer:
true!
Explanation:
if youre going by the scientific method, observations are mainly first. then questions, research, etc
Earth spins at 23.5
A day is one rotation
Answer : The molecule of ethane present in 64.28 L of ethane gas at STP is, 
molecule.
Solution :
At STP,
22.4 L volume of ethane present in 1 mole of ethane gas
64.28 L volume of ethane present in 
of ethane gas
And, as we know that
1 mole of ethane molecule contains 
molecules of ethane
2.869 moles of ethane molecule contains 
molecules of ethane
Therefore, the molecule of ethane present in 64.28 L of ethane gas at STP is, molecule.
The Texas City Refinery explosion occurred on March 23, 2005, when a hydrocarbon vapor cloud was ignited and violently exploded at the ISOM isomerization process unit at BP's Texas City refinery in Texas City, Texas, killing 15 workers, injuring 180 others and severely damaging the refinery.
