81.
What is the pH value of a neutral solution?
Explanation:
82.
Which element is the primary component of organic compounds?
Explanation:
83.
What is the chemical formula for methane, a common natural gas?
Explanation:
84.
What is the process of a solid changing directly into a gas without passing through the liquid phase called?
Explanation:
85.
Which gas is responsible for the "greenhouse effect" and global warming?
Explanation:
86.
Which element has the atomic number 1 and is the lightest of all elements?
Explanation:
87.
What is the term for a substance that speeds up a chemical reaction without being consumed in the process?
Explanation:
88.
Which noble gas is commonly used in lighting and advertising signs due to its bright red-orange glow when ionized?
Explanation:
89.
What is the term for a pure substance that cannot be broken down into simpler substances by chemical means?
Explanation:
90.
Which gas is produced during the process of photosynthesis in plants?