Mass number = protons + neutrons = 34+46 =80
the element with an atomic number of 34 and mass number of 80 is selenium
Answer:
A strong acid completely ionizes in water.
Answer:
See detailed explanation.
Explanation:
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i. In this case, since the given chemical reaction is exothermic due to the negative change in the enthalpy of reaction, we infer that according to the mentioned principle, by lowering the temperature the reaction will shift rightwards and therefore the yield is increased; thus, you need a lower temperature than the specified.
ii. In this case, since the reaction has less moles at the products side, according to the mentioned principle it'd be necessary to rise the pressure in order to increase the yield, since the increase of pressure favors the reaction side with the fewest number of moles.
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Pb + Mg(NO₃)₂ → Pb(NO₃)₂ + Mg
This reaction would NOT occur because Pb is less reactive than Mg and as such Pb cannot displace the Mg in order for the reaction to occur under normal conditions.
Mg + Fe(NO₃)₂ → Fe + Mg(NO₃)₂
This reaction would occur. This is because Mg is more reactive than Fe and as such can displace it in the reaction, thus allowing the reaction to occur under normal conditions.
Cu + Mg(NO₃)₂ → Cu(NO₃)₂ + Mg
This reaction would NOT occur. Mg is more reactive than Cu, and as such copper cannot displace magnesium in order for the reaction to occur under normal conditions.