Answer:

Explanation:
The unbalanced nuclear equation is

We can insert the subscripts, because these are the atomic numbers of the elements

That leaves only the superscript of He to be determined,
The main point to remember in balancing nuclear equations is that the sums of the superscripts must be the same on each side of the equation.
Then
27 + x = 31, so x = 31 - 27 = 4
Then, your nuclear equation becomes

Answer:
C
Explanation:
The Eukaryotic pre-mRNA receives a 5' cap and 3'poly(A) tail before Introns are removed and the mRNA is considered ready for translation.
Answer:
Br
Explanation:
Given data:
Mass of gas = 0.239 g
Volume of gas = 100 mL
Pressure exerted by gas = 603 mmHg
Temperature of gas = 14 °C
What is gas = ?
Solution:
Volume of gas = 100 mL (100mL ×1 L/1000 mL= 0.1 L)
Pressure exerted by gas = 603 mmHg (603/760 = 0.79 atm)
Temperature of gas = 14°C ( 14+273 = 287 K)
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
now we will calculate the number of moles.
n = PV/RT
n = 0.79 atm × 0.1 L / 0.0821 atm.L/ mol.K × 287 K
n = 0.079 /23.563 /mol
n = 0.003 mol
Molar mass of gas:
Number of moles = mass/molar mass
0.003 mol = 0.239 g/ molar mass
Molar mass = 0.239 g/ 0.003 mol
Molar mass = 79.7 g/mol
The molar mas of Br is 79.9 g/mol so it is closer to 79.7 thus given gas is Br.