1 half-life - 4.5 days
x half-lives - 27 days
x=(1*27)/4.5=6
6 <span>half-lives have elapsed after 27 days.</span>
C. (-2,-2) is the answer.
<u>Explanation:</u>
When we reflect a point (x, y) across the y-axis, after the reflection, the y-coordinate tends to be the same, however the x-coordinate is changed into its opposite sign.
Here U(2,-2) is reflected across the y-axis then,
the y-coordinate -2 remains the same and the x-coordinate is transformed into its opposite that is the sign of the x-coordinate will be changed as -2.
So the new coordinates of U after reflection will be (-2,-2).
This is the balanced eq
N2 + 3H2 -> 2NH3
first you need to find mole of N2 by using
mol = mass ÷ molar mass.
mol N2= 20g ÷ (14.01×2)g/mol
=0.7138mol
then look at the coefficient between H2 and NH3.
it is N2:NH3
1:2
0.7138:0.7138×2
0.7138:1.4276 moles
moles of NH3 = 1.4276 moles
Answer:
The one with the greatest mass would be the one that has the most things in the nucleus, protons and nutrons
Explanation:
You can't usually just use a single spectrum line to confirm the identity of an element because there are cases that the emission line id not clearly defined. When the emission line is very weak compared to surrounding noise, in which case the more datapoints you have to build up confidence for the existence of a particular emission spectra, the better.
