Answer:
The half-life of a radioisotope describes the amount of time it takes for said isotope to decay to one-half the original amount present in the sample.
Nitrogen-13, because it has a half-life of ten minutes, will experience two half-lives over the course of the twenty minute period. This means that 25% of the isotope will remain after this.
0.25 x 128mg = 32mg
32mg of Nitrogen-13 will remain after 20 minutes.
Answer:
The mass of CH4 is 60, 29 grams.
Explanation:
We use the weight of the atoms C and H for calculate the molar mass:
Weight of CH4= weight C+ 4 x weight H= 12,01 g/mol +4 x 1,008g/mol=
Weight of CH4 =16, 042 g/mol
1molCH4-----16, 042grams
3,758 mol CH4--X= (3,758 mol CH4 x 16, 042 grams)/1 mol CH4=60,285836 grams
16) Na (s) + H2O(L) ---> H2 (g) + NaOH (aq)
17) O2 (g) + NH3 (g) --->H2O (L) + HNO3 (aq)
18) K (s) + Cl2 (g) ---> KCl (s)
19) Al (s) + HCl (aq) ---> H2 (g) + AlCl (aq)
20) Na3PO4 (aq) + CaCl2 (aq) ---> NaCl (s) + Ca3(PO4)2 (s)
Answer:
Higher frequency
Explanation:
We can imagine a chemical bond between two atoms as if it were two balls connected by a spring.
According to Hooke's Law, the stretching frequency f is
where µ is the reduced mass of the system
The strength of the bond is analogous to k, the force constant of the spring. Then,
Thus, the stronger the bond, the greater the frequency of vibration.
