The effective nuclear charge is an innate property of a specific element. It is the pull of force that an electron feels from the nucleus. It is related to the valence electron by the equation: Z* = Z-S, where Z* is the effective nuclear charge, Z is the atomic number and S is the shielding constant.
For the following elements in the choices, these are their values of Z*:
Aluminum - +12.591
Beryllium - +1.912
Hydrogen - +1
Carbon - +4
The effective nuclear charge of Boron is +3. Thus, the answers are Aluminum and Carbon.
<span>When a chemical reaction occurs and the thermometer in the container records a drop in temperature t</span>he reaction is exothermic because heat was released by the reaction.
<span>B. The reaction is exothermic because heat was released by the reaction. is your answer.
Hoped I helped!</span>
Answer:
Explanation:
Hello,
In this case, the chemical reaction is:
Thus, we first identify the limiting reactant by computing the yielded moles of water by both of the reactants:
In such a way, since HBr yields less water than cadmium hydroxide, we infer that HBr is the limiting one, therefore, the yielded mass of water are:
Regards.
The equation for the nuclear fusion reaction is,
4 ¹₁H → ₂⁴He + 2 ₁⁰e
Calculation of mass defect,
Δm = [mass of products - mass of reactants]
= 4(1.00782) - [4.00260 + 2(0.00054858)]
= 0.0275828 g/mole
Given that,
Mass of Hydrogen-1 = 2.58 g
The no. of moles of ₁¹H = 2.58 g / 1.00782 = 2.56 moles
Therefore, the mass defect for 2.58 g of ₁¹H is,
= 2.56 moles * (0.0275828 g / 4) = 0.01765 x 10⁻³ kg
Energy for (0.01765 x 10⁻³ kg) is,
= (0.01765 x 10⁻³ kg) (3.0 x 10⁸)² = 1.59 x 10¹² J
Explanation:
The generated Na+ and OH-ions are immediately surrounded by molecules of water (typically 6, each). There is the development of the exothermic hydration sphere for each ion. It seems as though there is negative overall energy of dissolving solid NaOH.
Now, since this dissolution is exothermic the temperature of the mixture rises.
