In order to answer this, we mus know the data for the heat of combustion of propane. This is an empirical data that you can search online. The heat of combustion is -2220 kJ/mol. The molar mass of propane of 44.1 g/mol. The solution is as follows:
ΔH = -2220 kJ/mol (1 mol/44.1 g)(1000g/1kg)(20 kg)
<em>ΔH = -1006802.721 kJ or -1 GJ</em>
A lunar eclipse can be photographed sometimes when Earth is in between the sun and the Moon.
<h3>Why lunar eclipse occur?</h3>
A lunar eclipse occurs when the Sun, Earth, and Moon align in the same line in which the Moon passes into Earth's shadow. In a total lunar eclipse, the entire Moon falls within the darkest part of Earth's shadow, called the umbra so we can conclude that claim 2 is the right answer about lunar eclipse.
Learn more about eclipse here: brainly.com/question/1077760
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
Because it has more protons than electrons. Protons are positive so if there is more of them than electrons, the ion will have a positive charge.
An atom is the fundamental unit of matter and it contains an equal number of protons and electrons in its nucleus which makes it electrically neutral. An ion however, is an atom containing an unequal number of protons and electrons which means it will either carry a net positive charge or negative charge depending on whether there are more electrons or protons.
