Answer:
31.7 °C
Explanation:
Charles law states that for volume of a gas is directly proportional to the absolute temperature for a fixed amount of gas at constant pressure
we can use the following equation
V1/T1 = V2/T2
where V1 is volume and T1 is temperature at first instance
V2 is volume and T2 is temperature at second instance
temperature should be in kelvin scale
T1 - 0 °C + 273 = 273 K
substituting the values in the equation
22.4 L / 273 K = 25.0 L / T2
T2 = 304.7 K
temperature in celcius is - 304.7 K - 273 = 31.7 °C
the gas must be 31.7 °C to reach a volume of 25.0 L
First find the oxidation states of the various atoms:
<span>in Cr2O2 2- Cr @ +1; In NH3 N @ +3; in CrO3 Cr @ +3, N2 N @ 0 </span>
<span>Note that N gained electrons, ie, was reduced; Cr was oxidized </span>
<span>Now there is a problem, because B has NH4+ which the problem did not, and is not balanced, showing e- in/out </span>
<span>B.NH4+ → N2 </span>
<span>Which of the following is an oxidation half-reaction? </span>
<span>A.Sn 2+ →Sn 4+ + 2e- </span>
<span>Sn lost electrons so it got oxidized</span>
Answer:
B) the chemicals are gaining energy from the surroundings.
Explanation:
The positive sign of the energy difference in a chemical reaction would indicate that the chemicals are gaining energy from the surroundings. This is what happens in an endothermic reaction.
In an endothermic reaction, heat is absorbed from the surroundings hence the surrounding becomes colder at the end of the changes.
- Here the energy change is assigned a positive value.
- This is because the heat energy level of the final state is higher than that of the initial state.
- So, the difference gives a positive value.
