The number of half -lives that has passed after 105 hours for krypton-79 that has half-life of 35 hours is calculated as below
if 1 half life = 35 hours
what about 105 hours = ? half-lives
= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours
Oxygen and Sulfur are in the same group.
Sulfur is the next element in the group, and it reacts with hydrogen gas (H2) in a manner similar to oxygen.
Answer:
Chopping wood logs
A pot of water o a grate over a burning fire
Explanation:
Physical change is easily reversible. Burning/combustion is a chemical process where substances react rapidly with oxygen: this is usually irreversible.
The marshmallow, roasted food and burned wood all undergo combustion and hence are tagged chemical changes.
Explanation:
Explanation:
1: fluorine to form lithium fluoride
2:bcos covalent bond exists btw two non metals
3: bcos it is d combination of two or more elements nd elements r substances
4: for sbustances we hv flame test nd splint test
ionic compounds are held by strong electrostatic forces of attraction
Answer:
There is a physical change as the water is evaporating, producing a gas.
