Energy transfer
In the food coloring and water experiment, what happens to the particles in warm water compared to cold water?
They move faster in warm water, causing the food coloring to spread more quickly.
What visible evidence did we observe when baking soda and citric acid were mixed with water?
Bubbling and fizzing (gas formation).
When we measured the mass of the sealed bag before and after the baking soda and citric acid reaction, what did we notice?
Answer: The mass stayed the same.
What happens to atoms during a chemical reaction?
Answer: They rearrange to form new substances.
When baking soda and citric acid react in water, what happens to the temperature?
Answer: It decreases slightly.
In the metal cube and water experiment, why does the temperature of the water change when the hot metal cube is placed inside?
Thermal energy transfers from the hot metal to the cooler water until they reach equilibrium.
What type of matter was produced during the baking soda and citric acid reaction that was not present before?
Answer: Carbon dioxide gas.
Why does the mass of the system remain constant even though bubbles form during the reaction?
Answer: The gas stays inside the sealed bag, so no matter leaves the system.
In the baking soda and citric acid reaction, what evidence shows that new substances formed?
Answer: Gas bubbles and a temperature change.
What does a temperature decrease during a chemical reaction indicate about energy transfer?
Answer: The reaction is endothermic—it absorbs energy from the surroundings.
In the ice melting experiment, what energy transfer occurs when ice melts in warm water?
Thermal energy moves from the water to the ice, causing the ice to change state from solid to liquid.
Why does the mass of the closed system stay the same even though bubbles form during the reaction?
Answer: Matter is conserved; the gas stays inside the closed container.
What does the conservation of matter mean in terms of atoms during a chemical reaction?
Answer: Atoms are not created or destroyed; they are rearranged into new substances
Why do we use particle diagrams to model chemical reactions?
Answer: To show how atoms rearrange without being created or destroyed.
In the sealed bag experiment, why did the bag feel cooler after the reaction?
Answer: Energy was absorbed from the water and the bag as the reaction occurred.
During the particle motion simulation, what happens to particle spacing and speed when the temperature increases?
Particles move faster and spread farther apart as the temperature increases.
In the sealed bag experiment, what does the temperature change tell us about the chemical reaction?
Answer: It shows energy transfer—an endothermic reaction absorbed heat.
In the open container experiment, why did the mass decrease after the reaction?
Answer: Gas escaped into the air because the system was not closed.
When modeling the reaction between baking soda and citric acid, what stays the same before and after the reaction?
Answer: The total number of each type of atom.
How does measuring temperature before and after a reaction help us understand energy changes?
Answer: It provides evidence of whether energy was absorbed or released during the reaction.
Explain how the energy transfer in the hot metal and water experiment supports the idea that energy moves from warmer to cooler substances.
he metal loses thermal energy while the water gains it, demonstrating energy flows from high-temperature objects to low-temperature ones until equilibrium.
Explain how particle rearrangement during the baking soda and citric acid reaction supports the law of conservation of matter.
Answer: Atoms from the reactants rearrange to form new substances (products), but no atoms are lost or gained.
Explain how the sealed bag experiment provides evidence for the law of conservation of matter.
Answer: The total mass stayed the same before and after the reaction, showing that matter was conserved even though new substances formed.
Explain how the rearrangement of atoms in the baking soda and citric acid reaction supports the law of conservation of matter.
Answer: Atoms from the reactants are reorganized into products, but no atoms are lost or gained.
Explain how energy changes in the baking soda and citric acid reaction relate to particle rearrangement.
Answer: Breaking and forming bonds during rearrangement requires energy, which is absorbed from the surroundings, causing the temperature to drop.