Arock weighing 75.0 g is placed in a graduated cylinder displacing the volume from 31.4 ml to 36.5 ml. what is density of the rock in grams/cubic centimeter?
reactants, particles and atoms
petroleum refining or oil refining is a manufacturing method in which crude oil is removed from the ground, molded and purified into valuable products like liquefied petroleum gas (lpg), kerosene, asphalt base, jet fuel, gasoline, heating oil, fuel oils etc. crude oil contains hydrocarbon molecules. refining petroleum refining relates to the method of transforming crude oil into useful products. crude oil is made of hundreds of various hydrocarbon molecules, which are distributed by the method of refining.
how many moles of the reaction is needed to provide that 335 kj of heat?δh = -824.2 kj / mol according to the equation. in other words, each mole of the reaction releases 824.2 kj of heat. (the value of δh is negative, which means that the reaction produces energy.) 335 / 842.2 = 0.4307 mol. it takes 0.4307 moles of the reaction shown in the equation to produce all the 335 kj of heat.
how many moles of iron, fe in 0.4307 moles of the reaction?the coefficient in front of fe in the equation is two. as a result, each mole of this reaction would consume two moles of fe. the 0.4307 moles of the reaction will consume 2 × 0.4307 = 0.861 moles of fe to produce 335 kj of heat.
what's the mass of 0.8614 moles of iron, fe?refer to a modern periodic table, the relative atomic mass of iron fe is 55.85. as a result, the mass of one mole of iron fe is 55.85 grams. 0.861 × 55.85 = 48.1 grams. therefore, it takes 48.1 grams of iron to provide 335 kj of heat through this reaction.
answer: the correct answer is -c) prevent the embryo from drying out.
the amniotic egg of birds and reptiles is surrounded by an outer, tough, and protective shell, which protects the egg from any damage, predators, pathogens, and drying out.
the tough shell and extra embryonic membranes create a safe environment where an embryo can develop into a whole organism (with different organs like eyes ,ears, brain, kidney, heart).
thus, option c) is the right answer.