A tree getting struck by lightning, it is an example of a physical change.
It is so because when a tree getting struck by lightning, it encountered a strong force of power but no new substance is formed here. So it is a physical change, if it is a chemical change then a new substance must formed here. So when a tree getting struck by lightning, it is an example of a physical change.
A tree getting struck by lightning involves both physical and chemical changes but the most prominent change is physical due to the visible damage and the instant vaporization of the tree's sap.
When a tree is struck by lightning, both physical and chemical changes occur. The lightning's immense heat can cause the sap inside the tree to instantly turn into vapor which results in a physical change. Additionally due to the lightning's high temperature, some of the tree's matter could possibly undergo chemical reactions such as combustion, leading to new matter being produced, which is a chemical change.
However the most prominent change observed is physical, as the visible damage to the tree and the immediate change from solid to vapour state of the sap are the most noticable effects. Thus, in essence a tree getting struck by lightning mainly causes a physical change.
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To solve this we assume that the gas is an idealgas. Then, we can use the ideal gas equation which is expressed as PV = nRT. Ata constant temperature and number of moles of the gas the product of PV isequal to some constant. At another set of condition of temperature, theconstant is still the same. Calculations are as follows:
P1V1 =P2V2
V2 = P1 x V1 / P2
V2 = 153 x 4 / 203
V2 = 3 L
B. an endothermic reaction
C. a synthesis reaction
D. an irreversible reaction
Some molecules may contain no atoms.
B.
Some elements found in nature exist as molecules.
C.
Some compounds include only one type of element.
D.
Some atoms are made of two or more different elements. Which of these statements is true?
A.
Some molecules may contain no atoms.
B.
Some elements found in nature exist as molecules.
C.
Some compounds include only one type of element.
D.
Some atoms are made of two or more different elements.
Explanation:
It is known that at STP, there are 22.4 L present in one mole of a substance.
Therefore, in 68.5 liters there will be 1 mol divided by 22.4 L times 68.5 L.
Mathematically,
= 3.05 mol
Hence, we can conclude that there are 3.05 moles present in 68.5 liters of oxygen gas at STP.