Half-life<span> is the time required for a quantity to reduce to half its initial value. </span><span>If four half-lives have elapsed for calcium-45, then it would be 4x162.7 = 650.8 days have passed. Hope this answers the question. Have a nice day. Feel free to ask more questions.</span>
3 valence electrons are transferred in the formation of the compound potassium nitride because nitrogen needs 3 valence electron to become stable, or to have the electron configuration of noble Gases.
Pressure is 5.7 atm
<u>Explanation:</u>
P1 = Standard pressure = 1 atm
P2 = ?
V1 = Volume = 10L
V2= 2.4L
T1 = 0°C + 273 K = 273 K
T2 = 100°C + 273 K = 373 K
We have to find the pressure of the gas, by using the gas formula as,

P2 can be found by rewriting the above expression as,

Plugin the above values as,

Answer:
C. The reaction can be broken down and performed in steps
Explanation:
Hess's Law of Constant Heat Summation states that irrespective of the number of steps followed in a reaction, the total enthalpy change for the reaction is the sum of all enthalpy changes corresponding to all the steps in the overall reaction. The implication of this law is that the change of enthalpy in a chemical reaction is independent of the pathway between the initial and final states of the system.
To obtain MgO safely without exposing magnesium to flame, the reaction sequence shown in the image attached may be carried out. Since the enthalpy of the overall reaction is independent of the pathway between the initial and final states of the system, the sum of the enthalpy of each step yields the enthalpy of formation of MgO.
Answer:Yes they are in the same mineral group
Explanation:zinc is the central elements there. The rest of the elements are present as impurities due to where it was found. Like carbon is can be found in the soil, silicon with oxygen is basically sand, hydrogen is in the atmosphere and also in water and soil too. So apart from zinc, the rest are normal day to day elements.