Answer:
b) sharpening a pencil
Explanation:
If you melt lead, boil water, or dissolve sugar in water, you can return all of them back to their original state. If you sharpen a pencil, you can't reattach the shavings as they were originally.
You may put all of them back to their original states by melting lead, heating water to a boil, or dissolving sugar in water. You cannot rejoin the shavings from a sharpened pencil in their original position. Thus, option B is correct.
What is irreversible physical change?When something changes physically but not chemically, it has undergone an irreversible physical alteration that cannot be reversed.
Sharpening a pencil is a perfect example of an irreversible physical change. The wood turns to dust when you sharpen it. Just in a different shape, it is still wood. That wood dust cannot be transformed back into a pencil.
You cannot put a piece of paper back together the same way it was before you tore it if you tear it into tiny pieces.
An irreversible alteration is one that cannot be undone or that cannot be returned to its original state, such as when milk turns into curd, iron turns rusty, paper burns, food is cooked, etc.
Therefore, sharpening a pencil is an irreversible physical change
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What is the average atomic mass for Element X?
Answer:
the average atomic mass for element X is 28
A small block of wood floats on water. It has a volume of 25cm^3 and a mass of 20 grams. What is the density of the wood?
Answer:
The answer is 0.8 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{20}{25} = \frac{4}{5} \\ [/tex]
We have the final answer as
0.8 g/cm³Hope this helps you
CAN SOMEONE PLEASE HELP ME ASAP PLEASEE ANYBODY LITERALLY ANYONE OUT THERE PLEASE
It is the number of protons that determine
determine what?
please help asap !! i don’t know if that’s the right answer
Answer:
b, c and d (last three options)
Explanation:
It can't be the first one because:
On the left hand side there is one of everything and then on the right, ther is one zinc, two chloride and 2 hydrogen atoms. It is unbalanced
Second one:
there are 8 carbons on both sides, 20 hydrogens on both sides and 26 oxygen on both sides. It is balanced
Third
1 copper on both sides, 2 hydrogens on both sides and 1 oxygen on both sides. It is balanced
Fourth
4 silver on both sides and 2 oxygens on both sides
Which type of reaction has the general formula of AB + CD→ AD + CB
Answer:
Double replacement reactions
Explanation:
CD are two reactant compounds, while AB and CB are two product compounds that results from the reaction, in this type of reaction B and D change places
Observe: Scandium is the first element to contain electrons in the d subshell. How many orbitals does the d subshell have, and how many electrons can fit in the d subshell?
Answer: 5 orbitals
Explanation:
Each d subshell has 5 orbitals, with 10 electrons. So it's like for every orbital, there are 2 electrons. Look at orbital diagrams (if your teacher made you draw them), and you will see that an arrow pointing both UP AND DOWN represent 2 electrons (arrow upward=1 electron, arrow downward=1 electron)
Here, we are required to determine how many orbitals does the d subshell have, and how many electrons can fit in the d subshell.
The d subshell has 5 orbitals.The number of electrons that can fit in the d subshell is; 10 electronsThe d subshell is first recorded in the shell with energy level 3.
The orbitals in an atom are organized into different layers or electron shells. The d subshell has 5 orbitals in it.
This is evident from the formular; 2l + 1.
where l = 2 for the d subshell.
As with any sub-orbital, the sub-orbitals in the d-subshell also contain 2 electrons each.
According to Pauli's exclusion principle, the two electrons in each must have opposing spin.
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What is the negatively charged sub-atomic particle of an atom?
A) Proton
B) Neutron
C) Electron
Ciara’s bike has rusted, which means that the iron in the metal changed to rust.
What has occurred?
an energy formation
an exothermic reaction
a chemical reaction
a precipitate formation
Answer:
CChem Reaction
Explanation:
Cuz it big brain time
The iron in the metal changed to rust, which is a chemical reaction. Therefore, option (C) is correct.
What is the rusting of iron?The rusting of iron is an oxidation reaction in which the iron combines with oxygen in the air in the presence of water to produce Fe₂O₃.xH₂O, a hydrated iron (III) oxide.
This hydrated iron (Ill) oxide is rust and the color of rust is reddish-brown. This reddish-brown rust can be seen on iron nails, pipes, and railings. on. Rust is formed when the iron is exposed to oxygen in the presence of moisture and is not an instantaneous reaction. Rusting of iron takes place over a long period of time.
Fe (s) + O₂ (g) + xH₂O (l) → Fe₂O₃. xH₂O (s)
The oxidation state of iron increases which is followed by the loss of electrons as a result of the rusting reaction. Iron(III) oxide or ferric oxide has the iron atom has an oxidation state of +3.
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Carbon and hydrogen forms three different compounds A, B and C in which the percentage of carbon are 75%, 85.7% and 92.3% respectively. Which law of chemical composition can be illustrated with these data?
Answer:
Law of multiple proportions
Explanation:
The law which is illustrated with the data suggests the law of multiple proportion.
The combining elements are carbon and hydrogen;
Law of multiple proportions states that "if two element combine together to form tow or more different compounds, the masses of one of the elements which separately combine with a fixed mass of the other element are in a simple ratio".
Let us prove the law of multiple proportion:
In A;
C = 75% H = 25% = 3:1
B;
C = 85.7 H =14.3 = 6:1
C;
C = 92.3 H = 7.7 = 12:1
We see that both carbon and hydrogen have a fixed ratio.
how many valence electrons does tungsten have
Answer:74
Explanation:
Answer:
I believe Tungsten has 2 valence electrons.
Explanation:
Hope this helps!
PLSSS HELP WILL GIVE A LOOT OF POINTS
The diagram below shows two metal plates at different temperatures. Plate X is 30 degrees Celsius ( oC) and Plate Y is 50 degrees Celsius ( oC).
A.Plate X will become cooler and Plate Y will become cooler.
B.Plate X will become warmer and Plate Y will become cooler.
C.Plate X will become cooler and Plate Y will become warmer.
D.Plate X will become warmer and Plate Y will become warmer.
Answer:
I think B but I'm not sure.
Answer:
C.
Explanation:
What pair of elements have the same number of valence electrons?
a) Li and Na
b) Mg and K
c) Ti and Nb
d) Rb and Zr
The ans is A.
You need to refer back to the periodic table n find the 2 the is under the same grp.
Answer: its A
Explanation:
Heat is most closely related to which kind of energy? O nuclear Oelectrical thermal chemical
Answer:
thermal
Explanation:
Answer:
thermal energy
Explanation:
because thermal energy produces heat
What are diatomic molecules and are they compounds? PLEASE ANSWER ASAP!!
Answer:
Diatomic molecules consist of two atoms that are chemically bonded. The two atoms can be the same or different chemical elements. As for whether or not they are compounds, there is not technically an answer. This is because all compounds are molecules, but not all molecules are compounds. For example diatomic molecules that comprise the chemical compounds nitric acid, carbon monoxide, and hydrogen chloride are made up of two different elements. As you can see, most diatomic molecules are not made up of the same kind of elements and not every diatomic molecule comprises a chemical compound.
hope this helps :)
Explanation:
HELP QUICK What is the mass of an object that has a volume of 2 ml and a density of 10g/ml?
Answer:
The answer is 20 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question we have
mass = 10 × 2
We have the final answer as
20 gHope this helps you
A lunar eclipse is when the sun goes in front of the Moon?
Answer:
Explanation: When the Moon passes between Sun and Earth, the lunar shadow is seen as a solar eclipse on Earth. When Earth passes directly between Sun and Moon, its shadow creates a lunar eclipse. Lunar eclipses can only happen when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. Hope this helps and u have a good day <3
Calculate the answer. Express It In scientific notation. All answers should have the correct number of significant figures.
(4.9 x 10^-2) (9.80 x 10^2) =
48.02
48
48 x 10^-1
4.8 x 10^1
Answer:
4.8 x 10^1
Explanation:
Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the 10. If the decimal is being moved t the right, exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.
Help me balance this equation please.
NaCl + H2O —→ Cl2+ NaOH + H2
Answer:
2NaCl + 2H2O --> Cl2 + 2NaOH + H2
Explanation:
Family members on a camping trip decide to make hot cocoa after dinner. They add instant cocoa mix to hot water. What can they do to make the cocoa mix dissolve faster?
A stir the hot cocoa
B halve the amount of water
C double the amount of cocoa mix added
D add the cocoa mix after the water cools
Answer:
Your ANSWER:
A.stir the hot cocoa
Explanation:
stirring helps particals dissolve faster
In the reaction 4AI+_O2 2AI2O3, what coefficient should be placed in front of the O2 to balance the reaction?
Answer: 3
Explanation: I took the k12 quiz
Forces can be represented by _____,
called vectors, that show the direction of a force.
Answer:
vector
Explanation:
A ____________ contains specific instructions for making proteins.
a.
chromosome
b.
gene
c.
molecule
d.
ribosome
meaning of carbon cycle
The carbon cycle is nature's way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again. Most carbon is stored in rocks and sediments, while the rest is stored in the ocean, atmosphere, and living organisms
4 steps of Carbon Cycle
Photosynthesis, Decomposition, Respiration and Combustion.
Which word names melted rock and minerals found beneath Earth's crust?
A.lava
B.magma
C.rhyolite
D.gabbro
Answer:
B: Magma
Explanation:
technically magma is the name for the hot molten rock (mixed with gases and mineral crystals) that collects in chambers beneath the Earth's crust.
The crust has been the upper layer of the earth's geosphere. It has been characterized by the presence of melted rocks and minerals that are called magma. Thus, option A is correct.
What is magma?Magma has been defined as the hot semi-liquid president beneath the earth's surface in the crust layer. It has a very high temperature and is known to have many metals and minerals dissolved in it. The magma comprises metals minerals, dissolved gases, etc.
When the magma from the magma chambers flows outwards on the earth's surface then it is called lava. This lava on cooling produces igneous rocks. This event of magma explosion and lava formation along with other gases from a mountainous surface is called volcanic eruption.
Therefore, option A. melted rock and minerals in Earth's crust is called magma.
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A foam square has a mass of 25 g and a volume of 90 mL. What is the density?
Answer:
The answer is 0.28 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
So we have
[tex]density = \frac{25}{90} = \frac{5}{18} \\ = 0.277777...[/tex]
We have the final answer as
0.28 g/mLHope this helps you
Explain why the mass number of oxygen is 16
Answer:
Oxygen has an atomic number of 8 , and the mass number of an atom is the sum of its atomic number plus its neutron number. We got the mass as 16 units, and so it'll have 16−8=8 neutrons.
Explanation:
Please help me with this I’ve been on this question for 10 minutes now...
Answer:
A
Explanation:
we know that pangea was when all the continents were connected and the tectonic plates moved, causing pangea to split into multiple pieces. so north america was formed by moving tectonic plates.
i hope this helps :))
Sugar is added to iced tea and the contents are stirred until all of the sugar dissolves. How would the tea now be classified?
Gravitational potential energy depends on the strength of gravity, ________ and ________ of the object.
options:
height and mass
friction and movement
mass and movement
height and friction
The answer is A Height and Mass
Gravitational potential energy depends on the strength of gravity; A. height and mass of the object.
Gravitational potential energy (G.P.E) can be defined as the energy possessed by a physical object or body due to its position (height) above planet Earth.
Hence, gravitational potential energy (G.P.E) is highly dependent on mass, height of an object or body and the acceleration due to gravity.
Mathematically, gravitational potential energy (G.P.E) is given by the formula;
[tex]GPE = mgh[/tex]
Where:
G.P.E is the gravitational potential energy. m is the mass of an object. g is the acceleration due to gravity. h is the height of an object.In conclusion, the three (3) main factors that gravitational potential energy (G.P.E) depends on are:
I. Strength of gravity.
II. Height.
III. Mass.
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An atom has a mass number of 43 and an
atomic number of 23. How many protons
does it have?
Answer:
23 because the atomic number is base on protons and electrons and the neutrons is 20 hope it help
