A reaction in which heat is evolved is an exothermic reaction while a reaction in which heat is absorbed is an endothermic reaction.
In the first case; Na2CO3 + H2SO4, we can see that this is an acid - base reaction therefore it is a neutralization reaction. Since the tube was hot after reaction, heat is given off so it is exothermic.
In the second case; NaOH + H2SO4, we can see that this is an acid - base reaction therefore it is a neutralization reaction. We are told that the tube is not hot but we don't know the initial temperature of the tube or if it was colder than it's initial temperature so we can not make any inference regarding whether the reaction is endothermic or exothermic.
Lastly, the reaction, NaCl + HC2H5OH does not occur so we mark "no reaction". We are told that the tube is not hot but we don't know the initial temperature of the tube or if it was colder than it's initial temperature so we can not make any inference regarding whether the reaction is endothermic or exothermic.
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Use the de Broglie relationship between mass and wavelength (lambda).
lambda=h(Planck's constant)/[(mass)*(volume)]
lambda=6.626*10^-34/[(9.76*10^6)*(9.1094*10^-31)]
=7.45*10^-11 m
Liquid has a definite volume but no specific shape<span />
Fluid resistance refers to the forces a fluid places on a moving object in the opposite direction to the movement, also known as drag. Drag is the force created by a fluid to resist the motion of an object through it. There are 2 main sources of drag: pressure (form) and friction.
