Answer:
Copper ions are reduced into copper atoms.
Cu²⁺₍aq₎ + 2e⁻ → Cu₍s₎
Explanation:
During electrolysis, the positive H⁺ and Cu⁺ ions move to the negative cathode and negative OH⁻ and Cl⁻ ions move to the positive anode.
At cathode, copper ions are preferentially discharged due to the low electromotive force required to discharge them compared to the hydrogen ion. The copper ions gain the two electrons lost by the chloride ions when the are discharged. (2 Cl⁻₍aq₎ → Cl₂₍g₎ + 2e⁻)
Thus the half equation is as follows:
Cu²⁺₍aq₎ + 2e⁻ → Cu₍s₎
Answer:
squeezing syringes contain gas
24.6 ℃
<h3>Explanation</h3>
Hydrochloric acid and sodium hydroxide reacts by the following equation:
which is equivalent to
The question states that the second equation has an enthalpy, or "heat", of neutralization of 
. Thus the combination of every mole of hydrogen ions and hydroxide ions in solution would produce 
or 
of energy.
500 milliliter of a 0.50 mol per liter "M" solution contains 0.25 moles of the solute. There are thus 0.25 moles of hydrogen ions and hydroxide ions in the two 0.500 milliliter solutions, respectively. They would combine to release 
of energy.
Both the solution and the calorimeter absorb energy released in this neutralization reaction. Their temperature change is dependent on the heat capacity <em>C</em> of the two objects, combined.
The question has given the heat capacity of the calorimeter directly.
The heat capacity (the one without mass in the unit) of water is to be calculated from its mass and <em>specific</em> heat.
The calorimeter contains 1.00 liters or 
of the 1.0 gram per milliliter solution. Accordingly, it would have a mass of 
.
The solution has a specific heat of 
. The solution thus have a heat capacity of 
. Note that one degree Kelvins K is equivalent to one degree celsius ℃ in temperature change measurements.
The calorimeter-solution system thus has a heat capacity of 
, meaning that its temperature would rise by 1 degree celsius on the absorption of 4.634 × 10³ joules of energy. 
are available from the reaction. Thus, the temperature of the system shall have risen by 3.03 degrees celsius to 24.6 degrees celsius by the end of the reaction.
The balanced chemical reaction for the described reaction above is,
Na2CO3 + 2HCl ---> 2NaCl + H2CO3
From the reaction, 1 mole of Na2CO3 is needed to produce 2 moles of NaCl. In terms of mass, 106 grams of Na2CO3 are needed to produce 116.9 grams of NaCl. From this,
(23.4 g NaCl) x (106 g Na2CO3 / 116.9 NaCl = 21.22 g Na2CO3
Thus, approximately 21.22 g Na2CO3 is needed for the desired reaction.
