Answer:
lava is coming from the crust
Explanation:
volcano's explode with lava because the crust pushes it out
Answer: The density of the object will be 
Explanation:
Density is defined as the mass contained per unit volume.
Given : Mass of object = 19.6 grams
Volume of object= 
Putting in the values we get:
Thus density of the object will be
Weight percentage of nitrogen can be calculated using the following rule:
weight percentage of nitrogen = (weight of nitrogen / weight of urea) x 100
From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of nitrogen = 14 grams
molecular mass of hydrogen = 1 grams
molecular mass of oxygen = 16 grams
therefore:
mass of nitrogen in urea = 2(14) = 28 grams
mass of urea = 12 + 2(14) + 4(1) + 16 = 60 grams
Substitute with the masses in the equation to get the percentage:
weight percentage of nitrogen = (28/60) x 100 = 46.667%
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