Answer:
The correct option is A
Explanation:
An independent variable is <u>a variable that is intentionally altered (directly or indirectly) and is not dependent on another variable</u> in the course of an experiment. Unlike the independent variable, the dependent variable depends or is presumed to depend on the altered independent variables.
From the explanation above, it can be deduced that the concentration of the catalase is the independent variable as it was intentionally altered (by using different concentrations) in the course of the experiment. The amount of oxygen given off is the dependent variable here
Answer:
Explanation:
Pellet form of NaOH is highly hygroscopic . It absorbs moisture from air and its weight is increased by the time one tries to weigh one gram of it . Moreover it also reacts with carbon dioxide gas of atmosphere to form sodium carbonate .
2 NaOH + CO₂ = Na₂CO₃ + H₂0.
It also increases its weight .
Its a displacement reaction
Answer: An ionic bond is a bond that forms between ions with opposite charges.
Explanation:
A chemical bond formed by the transfer of electrons from one atom to another is called an ionic bond.
For example, sodium has electronic distribution as 2, 8, 1 and chlorine has electronic distribution as 2, 8, 7.
In order to attain stability, sodium needs to lose 1 electron and chlorine needs to gain one electron. Therefore, sodium will transfer its one valence electron (forming ion) to chlorine atom (forming ion) which leads to the formation of NaCl compound.
Thus, we can conclude that an ionic bond is a bond that forms between ions with opposite charges.