Answer:
t = 7.58 * 10¹⁹ seconds
Explanation:
First order rate constant is given as,
k = (2.303
/t) log [A₀]
/[Aₙ]
where [A₀] is the initial concentraion of the reactant; [Aₙ] is the concentration of the reactant at time, <em>t</em>
[A₀] = 615 calories;
[Aₙ] = 615 - 480 = 135 calories
k = 2.00 * 10⁻²⁰ sec⁻¹
substituting the values in the equation of the rate constant;
2.00 * 10⁻²⁰ sec⁻¹ = (2.303/t) log (615/135)
(2.00 * 10⁻²⁰ sec⁻¹) / log (615/135) = (2.303/t)
t = 2.303 / 3.037 * 10⁻²⁰
t = 7.58 * 10¹⁹ seconds
Answer:
B: +3
Explanation:
If Gallium loses 3 electrons, it will become an ion.
The ion will be positively charged because in this new ion, the number of electrons is lesser than the number of protons. The charge difference will impart a positive net charge on the ion.
- In a neutral atom, the number of electrons and protons are the same.
- For positively charged ions, the number of protons is greater than the electrons
If Gallium the loss of 3 electrons offsets the charge balance in the chemical specie. Thus, the ion will have a net +3 charge.
I think it’d be C. I’m not 100% if it is tho
This problem is requiring the empirical formula for CaCO₃, which is its molecular formula, and turns out to be equal, this is A. CaCO3 according to the following:
<h3>Empirical formulas:</h3><h3 />
In chemistry, molecular formulas show both the actual type and number of atoms in a chemical compound, based on the elements across the periodic table and the subscripts standing for the number of atoms in the compound.
However, the empirical formula is a reduced expression of the molecular one, which shows the minimum number of atoms in a compound after simplifying to the smallest whole numbers.
In such a way, since the given compound is CaCO₃ and both Ca and C have a one as their subscript, it is not possible to simplify any further and therefore the empirical formula equals the molecular one this time, making the answer to be A. CaCO3.
Learn more about empirical formulas: brainly.com/question/1247523
