To answer this question Kc of this reaction OR the conc of reactants nd products at equilibria is required.
Explanation:
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.
Learn more: brainly.com/question/11902331
I believe the correct answer is atmosphere
The unbalanced equation is BF3 + Li2 SO3 --> B2 (SO3)3 + LiF, where the numbers to the right of the symbols are subscripts. The balanced equation is 2 BF3 + 3 Li2SO3 ---> B2 (SO3)3 + 6LiF. The numbers in front of every formula (compound) are the respective coefficients. You can check that the equation is balanced counting every element: There are 2B in the side of the reactants and 2B in the side of the products; there are 6F in the side of the reactants and 6F in the side of the products; there are 6 Li in the side of the reactants and 6 Li in the side of the products; and there are 3 SO3 in the side of the reactants and 3 SO3 in the side of the products. <span>So, the coefficient of the LiF is 6.</span>
