Final answer:
Iron melting is an example of a physical change because it involves a state change without altering the substance's chemical composition.
Explanation:
An example of a physical change from the options provided is iron melting. Physical changes are characterized by a change in the state or properties of matter without altering its chemical composition. When iron melts, it changes from solid to liquid, but the substance remains iron; its molecules are not changed. Other examples of physical changes might include boiling water, dissolving sugar in water, or breaking a mirror. Conversely, wood decaying, paper burning, and steel rusting involve chemical reactions that create new substances, thus, they are chemical changes.
How can the rate of a reaction be increased?
-Rate of reaction is the speed at which the reactants are converted to products.
-Rate of reactions depends on a number of factors which includes;
Concentration of reactants; increasing the concentration of reactants increases the rate of reaction. Temperature; An increase in temperature results to an increased rate of reaction. Increase in temperature increases the kinetic energy of molecules thus the collision per unit time also increases and hence the rate of reaction increases.Decreasing the size of particles of solid reactants also increases the rate of reaction. This is because smaller particles increases the surface area on which more collisions can occur thus a faster rate of reaction.Adding a catalyst also increases the rate of reaction. This is because catalysts lower the activation energy of reactants, minimum energy require by reactants for the reaction to take place. This thus increases the rate of reaction.Explanation:
There are many factors that are responsible for increasing the rate of reaction.
(1) Temperature: If the temperature increases, the kinetic energy of the molecules also increases. Hence, the collisions and ultimately the rate of reaction increases.
(2) The concentration of reactants: Higher the concentration, more will be the collision and hence more will be the rate of reaction.
(3) Pressure: Pressure is also directly proportional to the rate of reaction.
(4) Catalyst: Adding a catalyst increase the rate of reaction. Because it decreases the activation energy of the reactants. Hence, a small amount of energy is required by the reactants.
Hence, the above factors increases the rate of reaction.
a 10 kg rock is suspended 320 m above the ground calculate the speed in which the rock hits the ground
compare the relationship between kinetic energy and mass with that of kinetic energy and speed.
When sugar is added to water, the sugar dissolves and the resulting liquid is clear. Have the combined sugar and water formed a pure substance or a mixture? Explain your a answer.
Which is not a disadvantage of the use of solar energy. *
a ____ agrees to help an immigrant become a citizen
investigations allow for the control of variables.
Is the star with the longest total lifetime Also the farthest from earth? Explain.
Stars with the longest lifetimes are not always the farthest from Earth, as factors like mass and luminosity influence a star's lifetime independently of its distance from Earth.
No, the star with the longest total lifetime is not necessarily the farthest from Earth. Stars can have different lifetimes based on their mass and luminosity, which affect how fast they burn their fuel. Distance from Earth is independent of a star's lifetime, and factors like apparent brightness and luminosity can play a role in how we perceive a star's distance.
If a 65 kg student exerts a force with a magnitude of 100 N on a 100 kg desk The magnitude of the force that the desk exerts on him is
Answer:
100
Explanation: Answer for CK-12
how does geosphere interact with biosphere
Which of the following is a characteristic of the sun energy arrive on Earth A.it cannot travel through the air B.It cannot travel through space C.It is made up of rays of varying frequencies. D.It is made up of rays of the same wavelength
Answer:
C-it is made up of rays of different wavelengths
Explanation:
It is because the sun produces rays of different wavelengths
i
The initial ___________ energy is equal to zero because the starting point is set at zero height to make things easier.
kinetic
potential
Answer: Potential energy
Explanation:
The initial potential energy is equal to zero. Potential energy is energy possessed by a body by virtue of its position. A body that is not moving is said to be in position and a body in position will have a zero velocity.
Jesse travels 3.0 meters east and then turns and travels 4.0 meters north. Which of the diagrams below illustrates his displacement
Answer: The second diagram.
Explanation:The arrow of the 3meters journey rests underneath the tail of the 4meters journey, and are both joined by the resultant 5meters vector joining the tail to the arrow
2. Which of the following is Not true about the noble gases? a. They have completely filled energy levels. b. They have weak intermolecular forces. c. They do not bond with other elements in nature. d. They have boiling points above room temperature.
The statement that is NOT true about noble gases is 'They have boiling points above room temperature.' Noble gases have low boiling and melting points due to weak London dispersion forces, they have filled energy levels, and they do not generally bond with other elements because of their stability.
Explanation:The statement that is NOT true about noble gases is 'd. They have boiling points above room temperature.' Noble gases, such as helium, neon, argon, krypton, xenon, and radon, have very low melting and boiling points.
This is due to the weak London dispersion forces that exist between the individual atoms. These weak forces can barely hold the atoms together which results in the low boiling and melting points.
Additionally, noble gases have completely filled energy levels and are stable, leading to the fact they rarely bond with other elements in nature. This stability is responsible for their name 'noble' as they are 'above' interacting with others, similar to nobility. So, the statements 'a. They have completely filled energy levels', 'b. They have weak intermolecular forces', and 'c. They do not bond with other elements in nature' are all accurate.
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explain why a car with a large mass might use more fuel than a car with a smaller mass. Assume both cars drive the same distance.
You and two of your friends go to the movies. Each ticket cost $7.50. You share the cost of the popcorn. If each person pays $9.05, how much was the popcorn?
Which of the following best explains why mutations cannot cause evolution?
Which statement is accurate for these two sub-atomic particles. A) They both have a neutral charge. B) They both have a positive charge. C) They are both located in the nucleus. D) They are both located outside the nucleus
Answer:
C!Explanation:
is one liter about an ounce a pint a quart or a gallon
Answer:
A quart
Explanation:
The conversion of different units in litres is defined below:
The value of 1 gallon is equal to 3.78541 litres.The value of 1 pint is equal to 0.473176 litre.The value of 1 ounce is equal to 0.0295735 litre.The value of 1 quart is equal to 0.94635 litre.Therefore, by seeing the above point the 1 quart is approximately equal to 1 litre.
what is the answer to this problem
Why is there diversity of life on Earth? A. so that young organisms can recognize their parents B. so that living organisms can survive and reproduce C. so that organisms create unique homes D. to encourage organisms to compete with each other
A person drives 20 miles north and 45 miles east. What is the angle of the resultant straight to their destination?
According to Freud which part of a persons personality is the largest
Final answer:
According to Freud, "the id is the largest part of a person's personality" because it encompasses instinctual drives and operates entirely in the unconscious.
Explanation:
According to Freud, the largest part of a person's personality is the unconscious, which includes the id, ego, and superego. While the ego operates in the conscious and serves as the mediator between the id and the superego, it is the id that forms the largest component, as it encompasses basic instinctual drives and is entirely unconscious. Freud's theory posits that the unconscious mind holds repressed memories and desires that significantly influence conscious behavior and personality development, with the id being a primary force driving pleasure-seeking behavior.
Which theory was revised to obtain the theory of plate tectonics?
Continental Drift Theory
Mid-Atlantic Ridge Theory
Pangea Theory
Seafloor Spreading Theory
Answer:
Explanation:
Continental Drift TheoryWhich of the following provide evidence for the theory of plate tectonics? Check ALL correct answers.
A) Land forms such as mountains have similar ages and composition despite being separated by oceans
B) Fossils of tropical plants have been found in northern Canada
C) Fossils of the fresh water reptile Mesosaurus are found in South America and Africa
D) Rock evidence of mountains on separate continents that match
E) Outlines of the continents fit together like puzzle pieces.
F) Sea floor spreading
Final answer:
Evidence for plate tectonics includes similar landforms across continents, the distribution of fossils in disparate geographic areas, the fit of continental outlines, and the process of sea floor spreading.
Explanation:
The evidence for the theory of plate tectonics is multifaceted and includes geologic, paleontologic, and morphologic observations:
Land forms such as mountain ranges that have similar ages, composition, and structure despite being separated by oceans are evidence of plate tectonics. For example, the Appalachian Mountains in North America are geologically similar to mountain ranges in Greenland and Europe, suggesting that they were once connected.Fossils provide evidence for plate tectonics. For instance, fossils of tropical plants found in northern Canada indicate that the area was once located in a different climate, possibly closer to the equator, before the plates shifted. Additionally, the presence of the freshwater reptile Mesosaurus' fossils in both South America and Africa suggests these continents were once joined.The complementary fit of the continental outlines, much like puzzle pieces, supports the idea that continents have drifted apart over time.Sea floor spreading is a process observed at the mid-ocean ridges, where new crust is generated and pushes plates apart, providing direct evidence of tectonic movements.By piecing together this evidence, scientists have been able to support the framework of plate tectonics, providing a comprehensive explanation for continental drift and the dynamic nature of the Earth's surface.
The mass of an object is equal to its weight true or false?
It is false that the mass of an object is equal to its weight, as it is never the same.
What is mass?In physics, mass is a quantitative measure of inertia, which is a foundational element of all matter.
It is, in effect, the opposition that a body of material provides to a change in its pace or position when a force is applied to it.
The smaller the change generated by an applied force, the greater the mass of the body.
The mass of an object is a fundamental quantification of its matter content.
Weight is a measurement of an object's gravitational force. It is determined not only by the mass of the object, but also by its location. As a result, weight is a measure of force.
A balance is used to measure mass. Mass can be measured in the lab using a triple beam balance or an analytical balance.
Thus, the given statement is false.
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The pituitary gland releases chemicals known as?
Answer: Endorphins
Explanation:
The pituitary gland releases chemicals that are called as endorphins. These are the polypeptides which are made by the pituitary gland as well as the central nervous system. These are a kind of hormone which helps in dealing with the situations of stress and reduces the pain.
The pressure effect associated with the hormone endorphins is the part related to the increase in concentration of the dopamine production due to the activity of endorphins.
Which of the following statements correctly compares ultraviolet and visible light?
A. UV light has more energy than visible light
B. UV light has lower frequency than visible light
C. UV light has a longer wavelength than visible light
D. UV light has a smaller amplitude than visible light
Final answer:
UV light has shorter wavelengths and higher frequencies than visible light, resulting in more energy, which is why statement A is correct.
Explanation:
The question asks which statement correctly compares ultraviolet (UV) and visible light. The correct answer is A, which states that UV light has more energy than visible light. This statement is accurate because in the electromagnetic spectrum, UV light has shorter wavelengths and higher frequencies than visible light, both of which contribute to its higher energy levels. Unlike visible light, the higher energy of UV light can be enough to break chemical bonds, such as those in DNA, which can lead to cellular damage and is why it is often blocked by sunscreen and sunglasses.
In which type of government is power centralized?
What is the best explanation of the importance of the Eighth Amendment?
A. If people cannot talk about policies, they cannot change them.
B. People in the military should have the right to vote in elections.
C. People accused of a crime need to be treated fairly to preserve justice.
D. People need to have the ability to protect themselves and their homes.
Answer:
D
Explanation:
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