why is the melting of ice a physical change
because a new substance forms
bescause the change is reversible
because the melting ice realizes energy
because the water has different properties than the ice
The correct answer is:
Because the change is reversible.
Melting ice is considered a physical change because it involves a change in the state of matter from a solid (ice) to a liquid (water), but no new substance is formed. The process of melting is reversible, meaning that water can be frozen to form ice again, indicating that it is a physical change rather than a chemical change. Additionally, the water that results from the melting of ice retains the same properties as the ice itself, such as its chemical composition.
what is the shape of earths orbit around the sun
The shape of Earth's orbit around the sun is an ellipse. An ellipse is a geometric shape that looks like a slightly elongated or stretched-out circle. In other words, Earth's orbit is not a perfect circle but a slightly flattened oval shape.
students are investigating north American bats they find that most of these bats eat insects many bats hibernate inside cool caves during winter
How does hibernation improve the ability of the bats to survive during the winter
it helps the bats survive when there is a food shortage
it gives the bats more energy to help them find food in winter
it helps the bats to hide from animals that eat them in the winter
it increases the body temp of the bats to keep them warm
The correct answer is:
It helps the bats survive when there is a food shortage.
Hibernation is a state of dormancy that allows bats to conserve energy and survive periods of food scarcity during the winter. By slowing down their metabolic rate, bats can lower their energy requirements and prolong their survival without needing to feed. This is particularly important because insects, the primary food source for many bats, are scarce during the winter months. Hibernation allows bats to endure the winter when their food supply is limited, increasing their chances of survival.
what do the atoms in group 1 of the periodic table have in commen
they have the same numbers of protons
they have the same number of electrons
they have the same number of electron shells
they have the same number of valence electrons
The correct answer is:
They have the same number of valence electrons.
Atoms in group 1 of the periodic table, also known as the alkali metals, all have the same number of valence electrons. Valence electrons are the electrons in the outermost energy level or shell of an atom. In group 1, all the elements have one valence electron. This similarity in valence electrons gives these elements similar chemical properties and reactivity.
4 Fe + 3 O2 ___Fe2O3
2
4
6
8
20
The balanced chemical equation for the reaction described is:
4 Fe + 3 O2 → 2 Fe2O3
This equation indicates that 4 moles of iron (Fe) react with 3 moles of oxygen (O2) to produce 2 moles of iron(III) oxide (Fe2O3). Thus, the coefficient in front of Fe2O3 is 2. So, the correct answer is 2.
which technology allowed astronauts to visit the moon for the first time on July 20, 1969
the telescope
artificial gravity
the space shuttle
large multistage rockets
The correct answer is:
Large multistage rockets.
The technology that allowed astronauts to visit the moon for the first time on July 20, 1969, was large multistage rockets. The Apollo missions, specifically the Saturn V rocket, were used to transport astronauts from Earth to the moon. The Saturn V was a three-stage rocket with enough power to break free from Earth's gravity and travel to the moon.