Answer:
A
Explanation:
We are usually asked to close the valve of the gas cylinder in our various kitchens at home <u>due to the inflammable property of the Liquified Petroleum Gas.</u>
<em>Without closing the valve, the LPG would diffuse into our homes, and any form of spark would cause an explosion and lead to a fire. Lives and properties could be lost in the process.</em>
The correct option is A.
Answer:
Fluorine > Selenium > Arsenic > Potassium > Argon
Explanation:
Electron affinity describes the ability or readiness or tendency of an atom to gain an electron.
The higher the value, the higher the tendency. Electron affinity depends on the on the nuclear charge and atomic radius. When nuclear charge is more, electron affinity is high, when atomic radius increases electron affinity reduces.
Noble gases such as Helium, Neon, and Argon would have 0 affinity for electrons because of their stable electronic configuration. From the list, Ar is the least in terms of electron affinity.
Potassium is a metal with large electropositivity which describes the tendency of an atom to lose electrons. Potassium would readily lose electrons instead of gaining.
Between Arsenic and Selenium: Arsenic belongs to group V and Selenium group VI. The two elements both belong to period IV on the periodic table. Across a period, electron affinity increases due to increase in nuclear charge. Therefore, Selenium would have a greater electron affinity compared to Arsenic.
Fluorine has the highest electron affinity of all. It needs just an electron to complete its octet.
Answer:
B. negative charge only
Explanation:
The saying "opposites attract" is true in the case. Since the rod is positively charged, the sphere must have a negative charge to be attracted to it.
A sphere that is positively charged would be repelled from the rod, and a neutral sphere would not be attracted or repelled.
Answer:

Explanation:
It often helps to write the heat as if it were a reactant or a product in the thermochemical equation.
Then you can consider it to be 11018 "moles" of "kJ"
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
M_r: 32.00
2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 8H₂O + 11 018 kJ
n/mol: 7280
1. Moles of O₂
The molar ratio is 25 mol O₂:11 018 kJ

2. Mass of O₂
