Answer: The nuclide symbol of X is 
Explanation:
The given nuclear reaction is a type of alpha decay process. In this process, the nucleus decays by releasing an alpha particle. The mass number of the nucleus is reduced by 4 units and atomic number is also decreased by 2 units. The particle released is a helium nucleus.
The general equation representing alpha decay process is:
For the given equation :
As the atomic number and mass number must be equal on both sides of the nuclear equation:
Thus the nuclide symbol of X is
Mass percentage is one way of representing the concentration of an element in a compound or a component in a mixture. To calculate percent by mass, you need to determine two things: the mass of just the element, and the molar mass of the whole compound. We calculate as follows:
.10 g NaCl / g NaCl + Water = ( 10.0 g NaCl + x ) / (10.0 g + 255 g + x )
x = 18.33 g NaCl needed
Answer: I think the answer is A
Explanation:
I’m sorry if I’m wrong.
1. ocean-> seashells -> limestone -> lithosphere
2. ocean -> marine plants -> sediments -> lithosphere
