Answer:
A
Explanation:
It is formed after the star has ended its star cycle into a supernova. The star collapsed into a neutron star that is smaller than the progenitor star but has inherited angular momentum. IT, therefore, spins faster emitting electromagnetic radiation that seems to pulsate.
Answer:
The correct option is C
Explanation:
From the question we are told that
The reaction is

Generally
Here
is the change in enthalpy
is the change in the internal energy
is the difference between that number of moles of product and the number of moles of reactant
Looking at the reaction we can discover that the elements that was consumed and the element that was formed is
and
and this are both gases so the change would occur in the number of moles
So
The negative sign in the equation tell us that the enthalpy
would be less than the Internal energy 
When water freezes into ice, some of the properties have change. What stays the same.
Answer: 1: Ice Melting is a physical change. When liquid water (H2O) freezes into a solid state (ice), it appears changed; However, this change is only physical as the the composition of the constituent molecules is the same: 11.19% hydrogen and 88.81% oxygen by mass.
Have a goood day!
Answer:
71.92 kPa
Explanation:
Using the combined gas law equation;
P1V1/T1 = P2V2/T2
Where;
P1 = initial pressure (kPa)
P2 = final pressure (kPa)
V1 = initial volume (L)
V2 = final volume (L)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the information provided in this question;
T1 = 50°C = 50 + 273 = 323K
V1 = 105L
T2 = -25°C = -25 + 273 = 248K
P2 = 105.4 kPa
P1 = ?
V2 = 55.0 L
Using P1V1/T1 = P2V2/T2
P1 × 105/323 = 105.4 × 55/248
105P1/323 = 5797/248
0.325P1 = 23.375
P1 = 23.375 ÷ 0.325
P1 = 71.92 kPa