The correct answer as to which observation most likely indicates that only a chemical change has taken place would that the change cannot be reversed.
When it comes to changes in a system, it can either be:
- physical change
- chemical change
When a substance undergoes a physical change, the original version of the substance can be recovered. In other words, physical changes can be reversible.
When a substance undergoes a chemical change, the original version cannot be recovered because an entirely new product would have been formed. In other words, chemical changes are irreversible.
Thus, once a change becomes irreversible, such a change is said to be a chemical change.
More on chemical change can be found here: brainly.com/question/1161517
Answer:
B. Decreasing the pressure applied to the gas molecules
Explanation:
According to Boyle's Law, the pressure of the gas is inversely proportional to the volume of the gas. So, the option B is correctly implied to it.
Other values such as Temperature, Number of molecules are inversely proportional to the volume of the gas.
Size of the gas molecules is negligible as compared to volume.
Answer:
138 mg
Explanation:
A company is testing drinking water and wants to ensure that Ca content is below 155 ppm (= 155 mg/kg), that is, <em>155 milligrams of calcium per kilogram of drinking water</em>. We need to find the maximum amount of calcium in 890 g of drinking water.
Step 1: Convert the mass of drinking water to kilograms.
We will use the relation 1 kg = 1000 g.

Step 2: Calculate the maximum amount of calcium in 0.890 kg of drinking water

The acid clouds fog the important nutrients like leave and needles . this loss of nutrient make it easier for infections , insects , and cold weather to damage trees and forests
Answer:
The rule is especially applicable to carbon, nitrogen, oxygen, and the halogens, but also to metals such as sodium or magnesium. ... All four of these electrons are counted in both the carbon octet and the oxygen octet, so that both atoms are considered to obey the octet rule.