Rate equation for first order reaction is as follows:
Here, k is rate constant of the reaction, t is time of the reaction, 
is initial concentration and 
is concentration at time t.
The rate constant of the reaction is 
.
(a) Let the initial concentration be 100, If 90% of the chemical is destroyed, the chemical present at time t will be 100-90=10, on putting the values,
Thus, time required to destroy 90% of the chemical is 23.03 days.
(b) Let the initial concentration be 100, If 99% of the chemical is destroyed, the chemical present at time t will be 100-99=1, on putting the values,
Thus, time required to destroy 99% of the chemical is 46.06 days.
(c) Let the initial concentration be 100, If 99.9% of the chemical is destroyed, the chemical present at time t will be 100-99.9=0.1, on putting the values,
Thus, time required to destroy 99.9% of the chemical is 69.09 days.
This answer is based on the electron configuration.
And you can use Aufbau's rule to predict the atomic number of the next elements.
Radon, Rn is the element number 86.
Following Aufbau's rules, the electron configuration of Rn is: [Xe] 6s2 4f14 5d10 6p6. This means that you are suming 2 + 14 + 10 + 6 = 32 electrons with respect to the element Xe.
You can verity that the atomic number of Xe is 54, so when you add 32 you get 54 + 32 = 86, which is the atomic number of Rn.
Again, as per Aufbau's rules, the next element of the same group or period is when the 6 electrons of the 7p orbital are filled. For that, they have to pass 32 elements whose orbitals are:
7s2 5f14 6d10 7p6: count the electrons added: 2 + 14 + 10 + 6 = 32, and that is why the next element wil have atomic number 86 + 32 = 118.
Now, when you go for a new series, you find a new type of orbital, the g orbital, for which the model predict there are 18 electrons to fill.
So the next element of the group will have ; 2 + 18 + 14 + 10 + 6 = 50 electrons, which means that the atomic number of this, not yet discovered element, has atomic number 118 + 50 = 168.
By the way the element with atomic number 118 was already discovdered at its symbol is Og. You can search that information in internet.
Answers: 118 and 168
Answer:
it says select all that apply hhh easy just select and apply the answer hhh
Explanation:
Answer:
a -4
b - 8
c - 5
d 2
Explanation:
Significant Figures: The number of digits used to express a measured or calculated quantity. By using significant figures, we can show how precise a number is. ... Accuracy: Refers to how closely individual measurements agree with the correct or true value.
The question is incomplete. Complete question is:
Which list represents the classification of the
elements nitrogen, neon, magnesium, and
silicon, respectively?
(1) metal, metalloid, nonmetal, noble gas
(2) nonmetal, noble gas, metal, metalloid
(3) nonmetal, metalloid, noble gas, metal
(4) noble gas, metal, metalloid, nonmetal
.................................................................................................................
Answer: The correct answer is option 2) nonmetal, noble gas, metal, metalloid
Reason:
1) Non-metal are bad conductors of electricity. Also non-metal are electronegative in nature. Hence, among the provided elements, nitrogen satisfied the criteria. Hence, it is a non-metal.
2) Noble gas are the elements which have completely filled outermost shell. Hence, among the provided elements, Neon satisfied the criteria.
3) Metal are good conductors of electricity. Also metal are electropositive in nature. Hence, among the provided elements, magnesium satisfied the criteria. Hence, it is a metal.
4) Metalloid have conductivity better than non-metals but poor than conductors. Hence, among the provided elements, Silicon satisfied the criteria. Hence, it is a metalloid.
