Chemistry: Properties and Changes of Matter

Which of the following is an example of a physical property that can be observed using our senses?

Which of the following is an example of a chemical change?

Which piece of equipment is NOT listed as being needed for this experiment?

What type of change does NOT alter the chemical composition of a substance?

During the experiment, what is the primary function of the de-ionized water?

In Part B of the experiment involving steel wool, what is being observed when the steel wool is heated on a hot plate?

Which of the following chemicals is used to observe the formation of precipitates in Part B of the experiment?

What safety precaution is mentioned in the procedure for handling hydrochloric acid (HCl)?

What does the experiment instruct you to do with any unused iodine after the solubility tests in Part A?

In the context of the experiment, what is the purpose of observing both physical and chemical properties of unknown substances?

Which of the following best describes the reaction when sodium metal is added to water?

Consider the reaction of cupric sulfate pentahydrate ($\text{CuSO}_4 \cdot 5\text{H}_2\text{O}$) when heated. What observation would indicate that the reaction is a dehydration process?

If the experimenter mistakenly heats iodine crystals in a closed, non-ventilated container instead of a fume hood, what is the most likely hazard that could occur?

Considering procedures 3-5 of Part 2 are done in a different order than written, what is the most significant concern regarding the identification of unknown substances?

Upon heating steel wool in an evaporating dish, an increase in mass is observed after the system cools. This observation primarily suggests which of the following?

What is the purpose of placing the sodium metal on filter paper before putting it on water in Part B of the experiment?

In Part B, after heating cupric sulfate pentahydrate crystals and allowing them to cool, water is added back to the crystals. What would be the expected observation if the reaction is reversible?

When sodium carbonate solution ($\text{Na}_2\text{CO}_3$) is mixed with hydrochloric acid ($\text{HCl}$), why is effervescence (bubbling) observed?

Why is it important to ensure there is plenty of space on the aluminum foil between each sample when heating them in Part 2 of the experiment?

During the experiment, you observe a solid dissolving in water. Which of the following observations would classify this process as a chemical change rather than a physical one?

What might be a consequence of using too much of a substance in the spot plate during Part 2 of the experiment?

Which of the following changes is most likely to be classified as a chemical change?

What is the primary goal of Chemistry Laboratory Activity #5?

Why is it important for a chemist to thoroughly describe a bit of matter?

Which of the following is a quantitative observation?

If a substance is transformed into a new substance, what kind of change has occurred?

Which of the following is a purpose of using a hot plate set to medium to heat a beaker containing iodine crystals covered with an evaporating dish filled with ice?

In the procedures described, what is the purpose of covering the beaker containing reacting sodium metal and water with a watch glass?

When testing the solubility of a substance in water, what observation suggests the substance is undergoing a chemical change rather than simply dissolving?

What is the most immediate risk of not wearing safety goggles during the experiment?

Which piece of equipment helps in the gentle mixing of substances in a well-plate?

What is the purpose of rinsing the iodine into a designated waste container after use?

Which of the following statements best explains why the experiment instructs you to observe the changes in substances after they cool to room temperature?

Which action will most likely reduce the risk of misidentification of an unknown substance in Part 2 of the experiment?

A chemist observes that a crystalline solid dissolves in water, and the resulting solution conducts electricity. After the water evaporates, the solid recrystallizes. This process is best classified as which type of change?

How would you classify a process where a substance changes directly from a solid to a gas without passing through the liquid phase?

In mixing sodium chloride and calcium chloride solutions with sodium carbonate, a white precipitate forms. If this precipitate is filtered, dried, and then treated with hydrochloric acid, effervescence is observed. What does this MOST STRONGLY indicate about the precipitate's composition?

Predict what would happen if, in place of de-ionized water, tap water was used consistently throughout the experiment. How would this affect the results and conclusions, if at all?

Which of the following best describes a physical change?

Which of the following is an example of a chemical property?

Which of the following is NOT considered a physical property that can be observed without measurement?

What is the key characteristic of a chemical change?

During Part A of the experiment, what is the purpose of using acetone and water with iodine?

Why is it important not to open any containers without the instructor's permission in Part A?

What does observing whether a substance is 'completely soluble, partially soluble, or insoluble' indicate?

In the experiment, what is the purpose of observing and recording properties of substances?

What is the purpose of using a fume hood when heating iodine crystals?

What is the purpose of adding phenolphthalein to the water when reacting sodium metal with water?

Which observation would most strongly suggest that heating cupric sulfate pentahydrate ($\text{CuSO}_4 \cdot 5\text{H}_2\text{O}$) leads to a chemical change?

Which of the following is the most likely reason for using de-ionized water instead of tap water in the solubility tests?

If, after heating steel wool, the observed mass significantly decreases, which of the following is the most probable cause?

In Part B, when sodium carbonate ($\text{Na}_2\text{CO}_3$) is mixed with hydrochloric acid ($\text{HCl}$), what gas is produced that causes the observed effervescence?

What can be inferred if a substance dissolves in de-ionized water but reacts when dilute acetic acid (vinegar) is added?

Considering that sodium metal reacts vigorously with water, what is the purpose of placing it on filter paper before putting it into the water?

What would be the most suitable method to distinguish between baking soda and baking powder, given the materials available?

Why might it be essential to use sufficient space between samples on the aluminum foil when heating them?

If mixing two clear solutions results in a cloudy mixture, which of the following is MOST likely occurring?

In the context of identifying an unknown substance, what is the significance of performing multiple tests?

Which of the following observations would indicate a chemical change when heating 'cupric sulfate pentahydrate'?

When heating iodine crystals, what is the primary purpose of placing ice in an evaporating dish on top of the beaker?

If, upon mixing two aqueous solutions, the resulting solution not only forms a precipitate but also changes color, what does this indicate about the reaction?

What property is being examined when a student tests whether a substance dissolves in water?

Which safety measure helps protect against chemical burns from hydrochloric acid?

What is a key difference between qualitative and quantitative observations?

Which of these is a quantitative property of a substance?

Which statement describes the arrangement of atoms during a chemical change?

Why is it important to describe a bit of matter as thoroughly as possible?

What does a chemical property describe about a substance?

What is the purpose of the glass stirring rod?

What evidence suggests a chemical change has occurred when testing a substance's solubility in water?

What is the function of the de-ionized water in the experiment?

What role does the hot plate play in experiments involving physical and chemical changes?

When sodium chloride and calcium chloride solutions are mixed with sodium carbonate, a white precipitate forms. Which of the following is the MOST LIKELY identity of this precipitate?

You add a few drops of hydrochloric acid (HCl) to a solution, and it begins to bubble. Which of the following substances are you most likely testing for?

During the steel wool heating experiment, what key observation suggests a chemical reaction has occurred?

What is the primary reason for washing your hands before leaving the lab?

Suppose you mix two colorless solutions, and the mixture not only turns blue, but it also spontaneously warms up. Which of the following can you conclude?