b. electronegavitiy decreases
electron affinity decreases as we proceed down a group.
the energy is radiant to thermal.
answer: the sound pitch (frequency) and the sound intensity (strength) of the car will decrease.
- as the distance between the source and the person increases, there must be more air molecules involved in transferring the sound leading to a decrease in the sound pitch (frequency “ number of sound waves received per second”).
- according to the inverse square law of sound “sound intensity is inversely proportional to the square of the distance between the source and the person”, as the distance between the source and person doubles, sound intensity (strength) will decrease to its quarter..
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.