Ice and Vaseline. Those are two melting compounds. When melting ice it turns into water and when melting Vaseline it melts into a oily liquid form. You can also freeze both of them and you can melt them again.
Answer:
C. As scientists have learned more about chemicals, they have become more aware of their dangers
Explanation:
Chemicals are substances with standard compositions, held together by chemical bonds. Chemicals can exist in different phases such as solid, liquid, and gaseous phases. Over time, with a growing understanding of chemicals, their composition, and their reaction methods, scientists now have a better knowledge of the dangers chemicals can pose. To that effect, they have created standard safety measures for those who have to work with these chemicals.
When these guidelines are strictly adhered to, the chances of suffering accidents, burns, and explosions with these chemicals are significantly reduced.
Answer: Dichotomous
Using a Dichotomous Key to Identify Organisms
A dichotomous key is a tool used by biologists to identify organisms in a group through a process of answering yes or no questions about the organism. Dichotomous means 'divided into two parts', as each question about an organism has two choices.
Charge of nucleus is always positive whether it is element or isotope.
Answer:
pH = 4.9
Explanation:
Given data
[H⁺] = 13 × 10⁻⁶ M
The pH is a scale used to determine <em>the acidity or basicity of a solution</em>. The pH is related to the concentration of hydrogen ions through the following expression.
pH = -log [H⁺]
pH = -log 13 × 10⁻⁶
pH = 4.9
Since the pH < 7, the soil is considered to be acid.
