Answer:

Explanation:
The number of valence electrons tells us the group number of the neutral atom.
The atom has 4 valence electrons.
The atom is in group 4.
Its a Reflector
Reflector is some sort of material that is used to collect or bounce off energy such as sound, light, or radio wave
Usually it took form in some sort of parabolic that revolve around an axis
Answer:
- 278.85 J
Explanation:
Given that:
Pressure = 1.1 atm
The initial volume V₁ = 0.0 L
The final volume V₂ = 2.5 L
The work that takes place in a reaction at constant pressure can be expressed by using the equation:
W = P(V₂ - V₁ )
Since the volume of the gas is expanded from 0 to 2.5 L when 1.1 atm pressure is applied. Then, the work can be given by the expression:
W = - P(V₂ - V₁ )
W = -1.1 atm ( 2.5 - 0.0) L
W = -1.1 atm (2.5 L)
W = -2.75 atm L
Recall that:
1 atm L = 101.4 J
Therefore;
-2.75 atm L = ( -2.75 × 101.4 )J
= -278.85 J
Thus, the work required at the chemical reaction when the pressure applied is 1.1 atm = - 278.85 J
<span>For number
two, the equation is balanced. Na in the reactant side has one atom and also in
the product side. O has only one atom in the product and in the reactant. There
are 2H’s in the reactant and in the product side (present in H2O, the 2 in H
stands for 2 atoms of H). One atom of Cl is present in the reactant and product
side.</span>
For number
three, the reactants are NaOH-sodium hydroxide and HCl-hydrogen
chloride(hydrochloric acid). The products are NaCl-sodium chloride and
H2O-water.
Answer:

Explanation:
To determine the age, we need to know how much U have become Pb, so first we have to calculate the Pb moles present in a sample:


The percentage of U degradation:


Assuming that the life time is linear:

