<h2>
Answer:</h2>
Nucleus.
<h2>
Explanation:</h2>
- In an atom the nucleus has an overall positive charge as it contains the protons.
- Every atom has no overall charge (neutral). While atoms do contain charged particles, they have the same number of positive protons as negative electrons( for example a sodium atom has 11 electrons which are of negative charge and 11 protons which are of positive charge).
- These opposite charges cancel each other out making the atom neutral.
Result: Nucleus is the overall positive charge of an atom.
Answer:
82.4 s
Explanation:
Find the NUMBEr of half lives...then multiply by 54.3
2.27 = 6.5 (1/2)^n
log (2.27/6.5) / log (1/2) = n = 1.52 half lives
1.52 * 54.3 = 82.4 s
Answer:
A) 1059 J/mol
B) 17,920 J/mol
Explanation:
Given that:
Cp = 29.42 - (2.170*10^-3 ) T + (0.0582*10^-5 ) T2 + (1.305*10^-8 ) T3 – (0.823*10^-11) T4
R (constant) = 8.314
We know that:

We can determine
from above if we make
the subject of the formula as:




A).
The formula for calculating change in internal energy is given as:

If we integrate above data into the equation; it implies that:



Hence, the internal energy that must be added to nitrogen in order to increase its temperature from 450 to 500 K = 1059 J/mol.
B).
If we repeat part A for an initial temperature of 273 K and final temperature of 1073 K.
then T = 273 K & T2 = 1073 K
∴



Increase in heat, molecules start to escape and it turns to vapor
Answer : The mass of sample is, 267.5 grams.
Explanation :
Density : It is defined as the mass of a substance contained per unit volume.
Formula used :

Given:
Volume of Pb = 
Density of Pb = 
Now put all the given values in the above formula, we get the mass of Pb.


Therefore, the mass of sample is, 267.5 grams.