James placed a breath mint and a lump of toothpaste in a cup of water and let it sit overnight. Which statement best explains why the breath mint was gone the following morning, but the toothpaste was still at the bottom of the cup?
The breath mint was less soluble than the toothpaste.
The breath mint was more soluble than the toothpaste.
The breath mint had a lower density than the toothpaste.
The breath mint had a greater density than the toothpaste.
Which substance would MOST neutralize an acidic food?
Dairy (pH 5-7)
Option 2
Citrus fruit (pH 2-3)
Baking soda (pH 8-9)
Which sentence about the periodic table of elements is true? *
All elements in period 2 are metals.
All elements in group 18 are metals.
Metals are found on the left side of the periodic table.
Metals are found on the right side of the periodic table.
Steel is a metal that is made from iron and carbon. During the steel making process, iron and carbon are melted, blended together, and then allowed to harden into a solid. The iron and carbon do not chemically react with each other. After steel was made, 20 samples were taken from one piece and tested. Each sample contained 98% iron and 2% carbon. Which of the following terms best describes steel?
element
compound
homogeneous mixture
heterogeneous mixture
5. Which is an example of a chemical reaction?
nails rusting
glass melting
sugar dissolving
alcohol vaporizing
Bromine (Br) is a liquid at room temperature. Oxygen (O) is a gas at room temperature. Room temperature is 25° C. Which of the following statements is true?
The boiling point of oxygen is colder than room temperature.
The boiling point of bromine is colder than room temperature.
The melting point of oxygen is warmer than room temperature.
The melting point of bromine is warmer than room temperature.
What are your answers?
1. To determine why the breath mint dissolved while the toothpaste did not, we need to understand solubility and density. Solubility refers to the ability of a substance to dissolve in another substance. If the breath mint was less soluble than the toothpaste, it means it did not dissolve as easily. Therefore, the statement "The breath mint was less soluble than the toothpaste" best explains why the breath mint was gone the following morning, but the toothpaste was still at the bottom of the cup.
2. To identify the substance that would most neutralize an acidic food, we need to consider the pH values. The pH scale ranges from 0 to 14, with lower values indicating acidity and higher values indicating alkalinity. Dairy has a pH range of 5-7, which is relatively closer to neutral (pH 7). Citrus fruit has a pH range of 2-3, indicating higher acidity. Baking soda has a pH range of 8-9, indicating alkalinity. Since we want to neutralize an acidic food, the substance that would most effectively do so is baking soda, with a pH of 8-9.
3. The statement "Metals are found on the left side of the periodic table" is true. The periodic table is organized based on various properties of elements, and metals are generally found on the left side. Non-metals, on the other hand, are mostly found on the right side or in the upper right corner of the periodic table.
4. Steel is a homogeneous mixture. A homogeneous mixture consists of two or more substances evenly distributed throughout, such that it appears uniform and the components are not easily distinguishable. In this case, the iron and carbon are blended together, resulting in a uniform composition throughout the steel. Therefore, the term "homogeneous mixture" best describes steel.
5. The example of a chemical reaction among the given options is "nails rusting." Rusting involves the reaction between iron (present in the nails) and oxygen in the presence of moisture, resulting in the formation of iron oxide (rust). This chemical reaction changes the composition of the nails, leading to their deterioration.
6. The statement "The boiling point of bromine is warmer than room temperature" is true. Bromine is a liquid at room temperature, indicating that its boiling point (the temperature at which it changes from a liquid to a gas) is higher than room temperature (25°C). In contrast, oxygen is a gas at room temperature, suggesting that its boiling point is lower, usually below room temperature.