Erosion, and I can’t see the other one so I’m assuming chemical reaction
Answer:
A positron is a subatomic particle with the same mass as an electron and a numerically equal but positive charge.
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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Answer:
2.0 moles S
Explanation:
To find the number of moles of S, you need to convert the moles Na to moles S via the mole-to-mole ratio. This ratio is represented by the coefficients in the balanced equation. Because you wish to find moles S, you want to put this number in the numerator. Because you want to eliminate the moles Na, this number should be in the denominator.
2 Na + 1 S ---> Na₂S
4.0 moles Na 1 mole S
---------------------- x --------------------- = 2.0 moles S
2 moles Na
C. Heat answer correct that
