1.When an exothermic phase change occurs, such as freezing water into ice crystals, where does the energy released go?
my answer: into the surroundings and the environment
2.When a flashlight battery runs out of energy (charge) does that mean the energy has been destroyed? Why or why not?
my answer:
energy is neither created nor destroyed, it just changes form, from chemical energy to electrical energy, and then electrical back to chemical, over and over again.
3.Describe what happens on the molecular level when hot water is poured over ice to melt it.
my answer: When hot water molecules collide with ice molecules, they transfer energy to the ice. This causes the ice molecules to vibrate. If they vibrate hard enough, they will break the bonds keeping them in the ice crystal and become liquid water.
4. Explain why wood insulates and metal conducts heat energy.
My answer: the molecules in the wood were bonded together when the tree was alive and producing new wood. The wood molecules are not free to bump into each other with the same energy of collision that the metal atoms in the fork have. The wood molecules are not able to transfer as much energy and so do not get as hot.
1. When an exothermic phase change occurs, such as freezing water into ice crystals, the energy released goes into the surroundings and the environment. This energy is transferred as heat as the water molecules lose energy and slow down during the freezing process. The energy can be absorbed by the air or other nearby objects.
2. When a flashlight battery runs out of energy (charge), it does not mean that the energy has been destroyed. According to the First Law of Thermodynamics, also known as the law of conservation of energy, energy cannot be created or destroyed, it only changes forms. In the case of a flashlight battery, the chemical energy stored in the battery's chemicals is converted to electrical energy, which then powers the flashlight. As the battery gets depleted, the energy is gradually transformed back into a different form, such as heat or chemical potential energy.
3. When hot water is poured over ice to melt it, on a molecular level, the hot water molecules collide with the ice molecules. During these collisions, energy is transferred from the hot water molecules to the ice molecules. This extra energy causes the ice molecules to vibrate more rapidly, which weakens the bonds holding them together in the ice crystal lattice. Eventually, the vibrations become strong enough to break these bonds, and the ice melts into liquid water.
4. Wood is a good insulator of heat because its molecular structure consists of tightly packed cells with air pockets in between. The air pockets act as insulation by trapping air and preventing the transfer of heat through conduction. Wood is a poor conductor of heat because the molecules within the material do not have the ability to efficiently transfer energy by colliding with each other. On the other hand, metal is a good conductor of heat because its atoms are closely packed and have loosely held outer electrons, allowing for fast and efficient energy transfer through collisions between atoms. This makes metals better at conducting heat compared to materials like wood.