Answer:
The correct answer is A. 3O₂ + 2Al → 2AlO₃
Law of conservation of mass states that mass can nether be created nor destroyed in a closed system or chemical reaction i.e. the total mass of the matter always remains the same throughout the chemical or physical change.
For example, in the given reaction 3O₂ + 2Al → 2AlO₃ the total mass of the reactants is equal to the total mass of the product.
Mass of oxygen = 16 x 3 = 48 AMU
Mass of aluminium = 2 x 27 = 54 AMU
Total molecular mass of the reactants = 102 AMU
Total molecular mass of the product = 2 x 27 + 6 x 8 = 102 AMU.
Hence, the total mass of the matter remains the same.
Psychology is a science because it follows the empirical method. ... We can directly observe and carefully measure externals such as what a person does, says, and marks down on a psychological test. We cannot directly observe a person's mind (e.g., internal thoughts, emotions).
<span>NA contains only elements, so it does not react easily. Many organisms do not contain DNA. Certain mutations in DNA happen at a constant rate. DNA does not change over time, making it a valuable clue.</span>
anatomy, molecular biology, and biogeography
Answer:
Hmm.
Explanation:
Measles is so contagious that if one person has it, up to 90% of the people close to that person who are not immune will also become infected. Infected people can spread measles to others from four days before through four days after the rash appears.
