so basically
some fuels have an impurity in them which is sulfur.
When the fuel undergoes combustion, the sulfur reacts with oxygen in the air to form sulfur dioxide.
the sulfur dioxide reacts with water vapour in the air to form sulfurous acid, which is a type of acid rain.
Also
the high pressures inside a car engine may cause nitrogen and oxygen in the air to react and form oxides of nitrogen. the most common compounds formed inside car engines are NO (nitrogen oxide) and NO2 (nitrogen dioxide)
A substance that is impenetrable by x-rays is described as being radiopaque.
Radiopaque substances will not allow x-rays and or other forms of radiations to pass through them.
Instead, they absorb or block the rays and when used in radiology, they appear white or light gray on photographic films.
Radiopaque materials are applied in generating ultrasound images and other forms of clinical procedures.
More on radiopaque materials can be found here: brainly.com/question/10583205?referrer=searchResults
The question is incomplete, complete question is :
In the Haber reaction, patented by German chemist Fritz Haber in 1908, dinitrogen gas combines with dihydrogen gas to produce gaseous ammonia. This reaction is now the first step taken to make most of the world's fertilizer. Suppose a chemical engineer studying a new catalyst for the Haber reaction finds that 348 liters per second of dinitrogen are consumed when the reaction is run at 205°C and 0.72 atm. Calculate the rate at which ammonia is being produced.
Answer:
The rate of production of ammonia is 217.08 grams per second.
Explanation:

Volume of dinitrogen used in a second = 348 L
Temperature of the gas = T = 205°C = 205+273 K = 478 K
Pressure of the gas = P = 0.72 atm
Moles of dinitrogen = n

According to reaction, 1 mole of dinitriogen gives 2 mole of ammonia.Then 6.385 moles of dinitrogen will give:

Mass of 12.769 moles of ammonia;
12.769 mol 17 g/mol = 217.08 g
217.08 grams of ammonia is produced per second.So, the rate of production of ammonia is 217.08 grams per second.
Answer:
-6.4x10⁻¹⁹ C
Explanation:
The elementary charge of one electron is -1.60x10⁻¹⁹C, so each electron has its charge, and a sample with more than one electrons will have a multiple of its charge, which is proportional to the number of electrons. So, if the oil droplet had 4 electrons, thus the charge will be four times the elementary charge:
4*(-1.60x10⁻¹⁹) C = -6.4x10⁻¹⁹ C