In an experiment to determine the percentage of humus content in a soil, the following results were obtained: mass of dish = 10 gm mass of dish and oven-dry...

To calculate the amount of humus in the soil sample, we need to use the formula: Humus content = (mass of organic matter / mass of dry soil) x 100 First, we need to find the mass of dry soil. We can do this by subtracting the mass of the dish from the mass of dish and oven-dry soil: Mass of dry soil = Mass of dish and oven-dry soil - Mass of dish Mass of dry soil = 50 g - 10 g Mass of dry soil = 40 g Next, we need to find the mass of organic matter. We can do this by subtracting the mass of the dish and soil after heating from the mass of the dish and oven-dry soil: Mass of organic matter = Mass of dish and oven-dry soil - Mass of dish and soil after heating Mass of organic matter = 50 g - 40 g Mass of organic matter = 10 g Now we can substitute these values into the formula: Humus content = (mass of organic matter / mass of dry soil) x 100 Humus content = (10 g / 40 g) x 100 Humus content = 25% Therefore, the amount of humus in the soil sample is 25% of the dry soil mass, which is equivalent to 10 gm of organic matter. Note: Humus is the organic matter in the soil that is left after decomposition of dead plants and animals. It plays an important role in soil fertility and helps to retain soil moisture.