A physical change is a change in the state or properties of matter without any accompanying change in the chemical identities of the substances contained in the matter. Physical changes are observed when wax melts, when sugar dissolves in coffee, and when steam condenses into liquid water. Other examples of physical changes include magnetizing and demagnetizing metals (as is done with common anti-theft security tags) and grinding solids into powders (which can sometimes yield noticeable changes in color).
The characteristics that distinguish one substance from another are called properties. A physical property is a characteristic of matter that is not associated with a change in its chemical composition. Familiar examples of physical properties include density, color, hardness, melting and boiling points, and electrical conductivity. Some physical properties, such as density and color, may be observed without changing the physical state of the matter. Other physical properties, such as the melting temperature of iron or the freezing temperature of water, can only be observed as matter undergoes a physical change
Figure :Copper and nitric acid undergo a chemical change to form copper nitrate and brown, gaseous nitrogen dioxide. During the combustion of a match, cellulose in the match and oxygen from the air undergo a chemical change to form carbon dioxide and water vapor. Cooking red meat causes a number of chemical changes, including the oxidation of iron in myoglobin that results in the familiar red-to-brown color change.
chemical change always produces one or more types of matter that differ from the matter present before the change. The formation of rust is a chemical change because rust is a different kind of matter than the iron, oxygen, and water present before the rust formed. The explosion of nitroglycerin is a chemical change because the gases produced are very different kinds of matter from the original substance. Other examples of chemical changes include reactions that are performed in a lab (such as copper reacting with nitric acid), all forms of combustion (burning), and food being cooked, digested, or rotting. Note that the number of atoms for a given element is calculated by multiplying the coefficient of any formula containing that element by the element’s subscript in the formula. If an element appears in more than one formula on a given side of the equation, the number of atoms represented in each must be computed and then added together. For example, both product species in the example reaction, CO2 and H2O, contain the element oxygen, and so the number of oxygen atoms on the product side of the equation is
(1 CO2 molecule × 2 O atoms per CO2 molecule) + (2 H2O molecules × 1 O atom per H2O(molecule) = 4 O atoms
The equation for the reaction between methane and oxygen to yield carbon dioxide and water is confirmed to be balanced per this approach, as shown here: CH 4 + 2O2⟶CO2 + 2H2O
Element Reactants Products Balanced?
C 1×1 = 1 1×1 = 1 1 = 1, yes
H 4×1 = 4 2×2 = 4 4 = 4, yes
O 2×2 = 4 (1×2) + (2×1) = 4 4 = 4, yes
A balanced chemical equation often may be derived from a qualitative description of some chemical reaction by a fairly simple approach known as balancing by inspection. Consider as an example the decomposition of water to yield molecular hydrogen and oxygen. This process is represented qualitatively by an unbalanced chemical equation: H2O⟶H2 + O2 (unbalanced)
Comparing the number of H and O atoms on either side of this equation confirms its imbalance:
Element Reactants Products Balanced?
H 1×2 = 2 1×2 = 2 2 = 2, yes
O 1×1 = 1 1×2 = 2 1 ≠ 2, no
H2O to H2 O2 would yield balance in the number of atoms, but doing so also changes the reactant’s identity (it’s now hydrogen peroxide and not water). The O atom balance may be achieved by changing the coefficient for H2O to 2.
2H2O⟶H2 + O2 (unbalanced)
Element Reactants Products Balanced?
H 2×2 = 4 1×2 = 2 4 ≠ 2, no
O 2×1 = 2 1×2 = 2 2 = 2, yes
The H atom balance was upset by this change, but it is easily reestablished by changing the coefficient for the H2 product to 2.
2H2O⟶2H2 + O2 (balanced)
Element Reactants Products Balanced?
H 2×2 = 4 2×2 = 4 4 = 4, yes
O 2×1 = 2 1×2 = 2 2 = 2, yes
These coefficients yield equal numbers of both H and O atoms on the reactant and product sides, and the balanced equation is, therefore:
2H2O⟶2H2 + O2
Types of Chemical Reactions
Humans interact with one another in various and complex ways, and we classify these interactions according to common patterns of behavior. When two humans exchange information, we say they are communicating. When they hit each other with their fists, we say they are fighting
A photograph is shown of a yellow green opaque substance swirled through a clear, colorless liquid in a test tube.
Hydrogen and oxygen undergo a chemical reaction to form water. How much water will be created if hydrogen has a mass of 3.56 g and the oxygen has a mass of 25.32 g?
Answer:
22.88g
Explanation:
Hope this helped <3
Oxygen in the air can react with wood when a match is burned. Ash is produced.
Which statement would be true?
A. The atoms of the ash did not exist before.
B. Ash has similar properties to oxygen.
C. The atoms of wood and oxygen disappear during the burning.
D. Ash is a different substance than wood.
Answer:
D. Ash is a different substance than wood.
Answer:
D the atoms of ash did not exist before
Explanation:
because I jnwo .... k
Martin slowly pours an unknown liquid into a container that originally had some water in it. He is measuring the temperature in the container as he does this.
The temperature in the container rises very fast.
What kind of change is likely to be happening in the container?
A. A physical change.
B. A chemical change.
C. Neither a chemical nor a physical change, only a temperature change.
D. No evidence of any type of change.
I need help with this please
Answer: C, the number of atoms stay the same
Explanation:
The number of atoms remains the same before and after the reaction. This is because of the Law of Conservation of Mass, which states that matter cannot be created or destroyed in a chemical reaction. In the case of methane burning, one molecule of methane (CH4) reacts with two molecules of oxygen (O2) to produce one molecule of carbon dioxide (CO2) and two molecules of water (H2O). The total number of atoms on both sides of the equation is conserved.
help me pls
words from the video:
What do fireworks, a fried egg, and a rusting vehicle have in common? They all involve chemical reactions. If two or more elements or chemical compounds come into contact with one another and there is enough energy present, a chemical change may take place.
When a substance undergoes a chemical change, the chemical structure of that substance is altered. A chemical change can also be called a chemical reaction. During a chemical reaction a new substance is formed.
Observe the chemical reaction between bromine and aluminum. Pieces of aluminum are cut from a strip of foil and added to liquid bromine. At first there is no reaction because of the protective oxide coating on the aluminum. But soon an exothermic reaction between bromine and aluminum causes brown fumes of bromine to be given off. But as a new substance, aluminum bromide is produced. White smoke is produced.
The resulting residue is also aluminum bromide. When two compounds or molecules react together to form new substances, they are called reactants. They new substances created plus any resulting ash, water vapor, or carbon dioxide are called products, because they are produced by the reaction.
Some chemical reactions, such as the explosion of fireworks, can happen very fast—in less than a second.
Others, like the rusting of a car, might take years. It is important to carefully examine chemical reactions because there are many ways substances can be changed without a chemical reaction taking place.
Changes of state, for example, from a solid to a liquid or from a liquid to a gas, always involve a physical change rather than a chemical one. Melting sulfur is a good example. When solid sulfur is heated to 120 degrees Celsius it melts and first forms a pale yellow liquid.
In this form the atoms are covalently bonded and the liquid can flow easily. However, heated up beyond 150 degrees Celsius, the result is a dark red liquid that is over 2,000 times stickier. The sulfur may have changed physically but it's still sulfur.
No chemical reaction has taken place. Most of the time changes of state can be reversed by either adding or taking away heat. When water is boiled, for example, water vapor molecules are released in the process.
If you captured all the vapor molecules in a container they would reform again as water droplets once the vapor cooled. When a chemical change occurs it is more difficult to revert the substance back to its original state.
Answer:
this is answers to the second picture
Explanation:
1- energy
2- structure
3- reaction
4- substance
5- reactants
6- products
7- changed
8- At first there is no reaction because of the protective oxide coating on the aluminum. But soon an exothermic reaction between bromine and aluminum causes brown fumes of bromine to be given off. But as a new substance, aluminum bromide is produced. White smoke is produced.
9- heated to 120 degrees Celsius it melts and first forms a pale-yellow liquid.
In this form the atoms are covalently bonded, and the liquid can flow easily. However, heated up beyond 150 degrees Celsius, the result is a dark red
10- When a chemical change occurs it is more difficult to revert the substance back to its original state. (To be honest I don't know)
What causes the seasonal changes viewed in the night sky?
Answer:
If you look at the night sky different
times of the year you see different
constellation.This change due to the
motion of the earth in it's orbit around
the sun.The shift of the sky is really
the motion of the earth around the sun.
Explanation:
Hope it helps
Explanation:
the factors which bring about the chemical reaction
why does atumn start in diffrent months of the year in north america and south america
Answer:
because the sun is further away due to the earth's axis
Name the 5 characteristics needed for a substance to be a mineral
naturally occuring, solid, inorganic, crystalline, structure, ans the same chemical composition throughout.
Answer:
A mineral has to be naturally occurring, inorganic, solid, crystal structure and definite chemical composition.
Explanation:
Helena uses the same force to move an object that has a mass of 12 kg and an object that has a mass of 5 kg. She predicts the 12 kg object will have a greater change in motion. Is she correct?
No, the object with the smaller mass will have a greater change in motion.
No, both of the objects will have an equal change in motion.
Yes, the object with the larger mass will have a greater change in motion.
No, neither object will have a change in motion.
Answer:
No, the object with the smaller mass will have a greater change in motion.
Explanation:
Hope this helps!
What will a soccer player need to do to change a ball’s position?
1. He must apply gravity to the ball so that the ball will move.
2. He must weigh the ball to determine the motion that needs to occur.
3. He must set the ball in motion by applying a force in the desired direction.
4. He must identify the location of the ball.
First one to answer will get brainliest!
Answer:
He must set the ball in motion by applying force in the desired direction.
Explanation:
That is how the soccer player will change the ball's position.
Have a good day :)
Answer:
4. He must identify the location of the ball.
Explanation:
If a soccer player needs to change his position, then he will need to identify the location of the ball.
hope this helped.
glacial striations in the bedrock of south africa indicate that glaciers once moved across the african continent the presence of glaciers on the surface of africa is evidence that
The presence of glaciers on the surface of Africa is evidence that it moved outwards from a central point in southern Africa.
What is a Glacier?This is defined as the persistent body of dense ice that is constantly moving under its own weight.
Glaciers being found on African surface depicts that the movement occurred outward from Southern Africa during the period.
Read more about Glaciers here https://brainly.com/question/6666513
Iodine-138 decays by beta decay. What element does it produce?
[tex] {xe}^{138} [/tex]
Explanation:
the bottom number would be 54. This is because you add one to 53 to make it 54 and you add 0 to 138.
Plz, Help! Read the instructions and answer the question! First one to answer will get brainliest!
Answer:
H₂S: Hydrogen Sulfide: 3 atoms
HCl: Hydrochloric acid: 2 atoms
NaCl: Sodium Chloride: 2 atoms
CaCO₂ : Calcium Carbonate: 3 atoms
Explanation:
I'm not sure about the answer but this is the best I could do hope it helps
since I'm a 9th grader I know something about this.
Answer:
wish i could help but i dont remember learning this
Explanation:
A food scientist is determined to create a mango that looks exactly like a mango but tastes like salmon. Can this be achieved through artificial selection? Why or why not?
You push on an object with an applied force. What is the "reaction" force to your push?
1. the object moving forward
2. the object being pulled by Earth
3. the object pushing back on you
4. the object being lifted up
Answer:
1. The object is moving forward.
Explanation:
How do wetlands form?
- tributaries flow into rivers.
• Runoff travels down the side of a divide.
ɷ Water builds up in a depression left by an ice sheet.
• Groundwater comes to the surface and floods the land.
take your time :) !
Answer:
I think it's "Water builds up in a depression left by an ice sheet."
Explanation:
I think.
An object has a mass of 960 g and a volume of 15cm3 what’s the density?
Explanation:
density = mass ÷ volume
mass = 960g
volume = 15³ = 15 × 15 × 15
= 3375 cm
density = 960 ÷ 3375
= 0.28 g/cm³
A food scientist is determined to create a mango that looks exactly like a mango but tastes like salmon. Can this be achieved through artificial selection? Why or why not?
Answer:
depends on the artificial 'materials' used and the food scientist
Explanation:
If the food scientist is skilled enough and works hard enough this it might be possible but this does seem like a difficult task i personally doubt that this could be done until next few years. :)
PLS HELP DUE SOON(Ignore that wet thingy on my paper it’s my matcha latte it go on it lol)
Answer:
well for
1. Because cytoplasm is made of a jelly like consistent
and
2. wastes product are transported by endoplasmic reticulum ,from organelles to outside cell ,so if cell size is big ,it will take more time in transportation and vice versa
Answer: Hello
Explanation: Hello
speed =________
ate divided by time
rate divided by distance
distance divided by time
time divided by rate
I need answer asap! Plz someone help ! Ill give brainliest!
Answer:
Distance divided by time is the answer. :)
Explanation:
Which phrase describes a feature of groundwater?
-feeds rivers
--provides habitats
-makes up 75% of fresh water
--used for hydroelectric power
Answer:
number 1
Explanation:
Groundwater mainly contributes the water into the surface water like streams, rivers, and lakes.
Groundwater feeds rivers describes it feature.
What is ground water?Groundwater refer to the water that is below Earth's surface and they infiltrate the fractures of rock formations and spaces between sediments.
Ground water replenish the rivers, streams and lakes.
Therefore, Groundwater feeds rivers describes it feature.
Learn more on groundwater from the link below.
https://brainly.com/question/9617
HELPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!!!! 30 POINTS!!!!!!!!!!!!!!
Answer:
What is this please send questions properlythen i will answer it properly
Please help!!! Hydrogen and oxygen undergo a chemical reaction to form water. How much water will be created if hydrogen has a mass of 3.56 g and the oxygen has a mass of 25.32 g?
Actual answers only please :)
Answer:
22.88g
Explanation Hope this helped <3
PLS HELP (science)
Match the following molecules with the number of atoms they contain.
1. 2Fe
seven
2. 2Al 3O 2
eight
3. 4O 2
two
4. 5C
five
5. H 2SO 4
ten
Answer:
hello I will answer ur question if u answer mine
Explanation:
Place the events in the order that they must occur for a fossil to be formed in sedimentary rock.
In a chemical reaction, the mass of the reactants is 13.3 grams. Which of the following could represent the mass of the products?
A. 26.6 grams.
B. 13.3 grams.
C. 39.9 grams.
D. 3.3 grams.
Answer:
Hi the answer should be 13.3
Explanation:
Hope this helps! :D
What type of force is known for exerting an upward force on objects in a fluid?
1. buoyant force
2. friction force
3. gravitational force
4. magnetic force
The First person to answer will get the brainliest!!!!!!
Answer:
The answer is 1, Buoyant force.
Explanation:
can someone solve this question please
Answer:
MgO + 2 HNO3 → Mg(NO3)2 + H2O
Explanation:
This is the chemical formula of Nitrogen gas.
N₂
Which of the following is NOT true of nitrogen gas?
A. It is made of two atoms.
B. It is a molecule.
C. It is an element.
D. It is a compound.
Answer:
D
Explanation:
N₂ is not a compound because it is not made up of two or more different elements - it is only made up of nitrogen atoms
Hope this helps!
PLEASE HELP
Sheila and Jerome are lab partners. They have the following materials at their table:
1 square of aluminum foil, 1 stirring rod, 1 beaker of water, 1 scoop of copper II chloride salt (blue color)
Step 1:Jerome adds all the salt to the water and stirs. The salt crystals disappears and the liquid solution turns a clear blue.
Step 2: Sheila tears up the aluminum foil into small pieces.
Step 3: Jerome dares her to put the foil in his beaker. They see the edges of the foil turn a rusty orange. As they stir, the beaker becomes warm to the touch and a vapor begins to rise from the surface of the beaker. Within a few minutes, the foil has disappeared and the liquid is now clear. There are orange-rust colored flakes floating in the liquid.
Q: Jerome claims that when the salt was added to the water it turned blue and the foil disappeared, these were chemical changes. He went on to explain that the chemical change was due to the fact that the atoms were speeding up. Sheila disagrees claiming that 1 is a physical change and 1 is a chemical change and Jerome’s evidence is incorrect. Who is correct, Jerome or Sheila? Write a scientific explanation (CER) to support your argument.
Answer:
jerome
Explanation: