JAMB - Biology (2000 - No. 27)
In an experiment to estimate the volume of air in a soil sample using a measuring cylinder, it was found that:
initial volume of water .... = p cm3
volume of soil before mixing with water = q cm3
Final volume of water after adding soil = r cm3
From the data above, which of the following deductions is correct?
initial volume of water .... = p cm3
volume of soil before mixing with water = q cm3
Final volume of water after adding soil = r cm3
From the data above, which of the following deductions is correct?
r = p + q
r > p + q
q = r - p
r< p + q
Giải thích
To estimate the volume of air in a soil sample using a measuring cylinder, you can calculate the difference between the total volume of the soil and water mixture and the observed volume of the mixture:
- Calculate the total volume of the soil and water mixture, (p+q)cm3
- Observe the total volume of the water-soil mixture, r cm3
- Subtract the observed volume from the total volume to calculate the volume of air. In other words, r < (p + q), because on mixing with water, air present in the soil would have been released and escaped from the soil.