Answer:
D) 21.9
Explanation:
1 kilocalorie is equal to 4184 joules
0.001 kilocalorie is equal to 1 calorie
so 5.25 calorie=21.966 joules
I think its 2-, it gained 2 electrons.
Answer:
Half-Life = 18 days
Explanation:
Isotope decay follows the equation:
Ln[A] = -kt + ln[A]₀
<em>Where [A] is amount of isotope after time t,</em>
<em>k is rate constant</em>
<em>[A]₀ is initial amount of isotope.</em>
<em> </em>
If we solve rate constant, we can find half-life by using:
Half-life = ln 2 / Rate constant
Replacing in isotope decay equation:
Ln[1/8] = -k*54 days + ln[1]
-2.07944 = -54k
0.0385days⁻¹ = k
Half-Life = ln 2 / 0.0385days⁻¹
<h3>Half-Life = 18 days</h3>
<em />
Answer:
4.76
Explanation:
In this case, we have to start with the <u>buffer system</u>:
We have an acid () and a base (). Therefore we can write the <u>henderson-hasselbach reaction</u>:
If we want to calculate the pH, we have to <u>calculate the pKa</u>:
According to the problem, we have the <u>same concentration</u> for the acid and the base 0.1M. Therefore:
If we divide:
If we do the Log of 1:
So:
With this in mind, the pH is 4.76.
I hope it helps!
Answer:
A high difference in electronegativity will be present in ionic compounds since the electrons are transffered from the element less electronegative to the element more electronegative.
A small difference in electronegativity is present in molecular compounds (covalent bonds). None of the elements is strong enough to attract the electrons so the electrons are shared.
Explanation:
A high difference in electronegativity will be present in ionic compounds since the electrons are transffered from the element less electronegative to the element more electronegative.
A small difference in electronegativity is present in molecular compounds (covalent bonds). None of the elements is strong enough to attract the electrons so the electrons are shared.