Answer:
18
Explanation:
In neutral atom protons and electrons are equal in number as it atomic number or proton number is 18 so electrons are also 18
The total number of electrons in an atom of an element with an atomic number of 18 and a mass number of 40 is 18.
What are the difference between atomic number and atomic mass ?Atomic mass can be defined as the total number of neutrons and protons located in nucleus of an element while atomic number is the number of protons present in the nucleus of element.
Atomic mass can be defined as the average weight of an element where as the atomic number is the total number of protons present in the nucleus; Atomic mass have the symbol A while atomic number have the symbol the letter Z.
Different isotopes of an element are differentiated by atomic mass is while isotopes share the same atomic number, in neutral atom protons and electrons are equal to atomic number or proton number is 18 and electrons are also 18
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Two seventh grade students are studying how sound waves are transferring energy.
They beat a pot and the sound waves cause waves in the glass of water.
How would the students increase the amplitude of the waves in the glass of water?
Hit the pot softer with less energy
Hit the pot harder with more energy
Hit the pot faster at a higher frequency
Hit the pot faster at a slower frequency
Answer:
Hit the pot faster at a higher frequency
Explanation:
I feel like it would be because it makes more sense to me but I really have no clue tbh
d) velocity ratio =_________ Iload distance
Answer:
velocity ratio is defined as the ratio of distance moved by effort and load in the same time interval
Explanation:
can I get help please
*please be serious *
How does digestion and transport interact to keep and organism alive ?
Answer:
Explanation:
Digestion breaks down the food or nutrients taken in by the organism into a form of energy that is then transported to areas of the organism where it is needed. Along with transporting the waste to exit the organsim because the waste is no longer needed as digestion has extracted its nutrients.
In a metal lattice, the metal ions are _____ and they are _____.
Answer:
a.)cations; free to move around
b.)cations; fixed in place
calculate the ratio of molecules present in 16g of methane and 16g of oxygen
Answer:
The ratio = 2 : 1
Explanation:
I WILL GIVE BRAINLEST IF YOU ANSWER THIS QUESTION QUICKLY!!!
what is an orbital?
Answer:
Electric Patterns and has many different variations.
Explanation:
A student added 5 grams of calcium chloride, a white solid substance, to 15 grams of water at 220 C. Several observations were made and the student inferred that a chemical reaction occurred.
Which observation best supports the student's inference that a chemical reaction occurred?
Answer:
D
Explanation:
A The calcium chloride dissolves in solution
B The mass of the solution totals 20 g
C The temperature of the solution is 35 degrees
D The solution became lighter in color
The correct answer would be that the solution became lighter in color.
An increase in temperature can also be considered a sign of a chemical reaction but in this case, the dissolution of calcium chloride in water is in itself exothermic.
A change in the mass of the final solution could also be considered a sign of a chemical reaction but in this case, the total mass equals the addition of the individual masses of the reactant.
The dissolution of calcium chloride in water is not enough as evidence of a chemical reaction. Dissolution can be a physical change of which, the evaporation of the water would retrieve the solute.
A change in color, however, is one of the evidence to establish that a chemical reaction has occurred.
The correct option is D.
What is the difference between active transport and facilitated diffusion?
Answer:
Active transport is an active process. Thus, it requires energy. Whereas facilitated diffusion is a passive process and does not require energy.
Explanation:
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Which statement correctly describes how a landform is created?
A canyon is created when ice from a glacier slowly melts over time.
A delta is created when wind blows large amounts of soil toward the shore
A sand dune is created when an earthquake breaks large rocks into small particles.
A V-shaped valley is created when a fast-moving river carves steep sides into hills and mountains
As bond number increases (double bonds rather than single, triple rather than double etc.), bond length and bond energy . Group of answer choices Decreases, increases Decreases, decreases Increase, increases Increase, decreases
Answer:
Decreases, increases
Explanation:
Depending on the number of electrons shared, covalent bonds may be single, double or triple. In a single bond, two electrons are shared between bonding atoms. In a double bond, four electrons are shared between bonding atoms while in a tripe bond, six electrons are shared between bonding atoms.
The number of bonds is otherwise referred to as the bond order. The higher the bond order the higher the bond energy and the shorter the bond length. The bond length shortens due to an increase in the s character of the bond.
How many moles of manganese in 4.07 x 1024 atoms of manganese?
Answer:
6.76 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{4.07 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 6.760797...[/tex]
We have the final answer as
6.76 molesHope this helps you
Plz I need help with this stuff!!!!!!!!!brainly wouldn’t let me post the other pics
An ice skater moves back and forth on an ice rink. She speeds up on the straight portion of the rink. She slows down near each end of the rink and then turns around. Which claim supported by evidence?
The options are;
A) The skater experiences acceleration both while skating in a straight line and while making her turn.
B) Because the skater does not change her direction or speed, she does not experience acceleration.
C) The skater only experiences acceleration when she is turning.
D) The skater only experiences acceleration while skating in a straight line.
Answer:
A: The skater experiences acceleration both while skating in a straight line and while making her turn
Explanation:
We are told that She speeds up on the straight portion of the rink. This means that she experienced an acceleration since the speed was not constant but gradually increasing.
Also, we are told that She slows down near each end of the rink and then turns around. This means that she reduced speed before turning and it means there was also an acceleration as well when making the turn.
Thus, she experience acceleration both in the straight line and when making turn.
Option A is correct
How many atoms are there in 32.45 grams of Magnesium?
Answer:
8.13 ×10²³ atoms
Explanation:
Given data:
Mass of magnesium = 32.45 g
Number of atoms = ?
Solution:
Number of moles of Mg:
Number of moles = mass/molar mass
Number of moles = 32.45 g/ 24 g/mol
Number of moles = 1.35 mol
Number of atoms:
1 mole contain 6.022×10²³ atoms
1.35 mol × 6.022×10²³ atoms/ 1mol
8.13 ×10²³ atoms
Which element is probably most like Carbon? and why
Gina summarizes the ideas that led to the current atomic model.
1. Dalton developed the theory that all matter is made of atoms.
2. Thomson discovered that atoms contain electrons.
3. Rutherford discovered that atoms have a nucleus.
4. Schrödinger developed the electron cloud model.
5. Bohr developed the model in which electrons orbit the nucleus.
Which change should Gina apply to correct the summary?
Switch 1 and 5.
Switch 2 and 3.
Switch 4 and 5.
Switch 3 and 1.
Answer:
C. Switch 4 and 5
Explanation:
edge2021
The atomic model gives a detailed understanding of the atoms and the sub-atomic particles. The models were given in order by Dalton, Thomson, Rutherford, Bohr, and Schrödinger. Thus, option C is correct.
What is the atomic model?
The atomic model is the representation of the atom of the element along with the sub-atomic particles. The first model was given by Dalton, which stated that matter is composed of atoms.
Later Thomson discovered the presence of the electron present in the sea of the positive charges. In addition, Rutherford gave the presence of the positive nucleus in the middle of the atom.
Bohr's model gave the presence of the electron in the orbit of the atom around the nucleus. At last, the current atomic model was given by Schrödinger and is known as the electron cloud model.
Therefore, option C. Gina should Switch 4 (Schrödinger' model) with model 5 ( Bohr 's model).
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Please answer correctly !!!!!!!!!!!!!!! Will mark brainliest !!!!!!!!!!!!!!!!!!!!
Answer:
i dont have an answer for sure because it doesnt specify WHAT its energy chang occurs but i think its physical change
Explanation:
Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.
examples of chemical change:
burning a fire
boiling an egg
digestion
examples of physical change:
melting ice
rusting
breaking a pencil
hope i helped!!
What is the difference between elements and compounds? *
why a marble would be a good representaion of the inner core
Answer:
Marble forms when a pre-existing limestone rock is heated to such extreme temperatures that the minerals grow larger and fuse together. With this in mind, a hard marble rock would be the perfect example of the inner core of Earth since its packed, and full of high heat levels.
Explanation:
Which of the following correctly lists the organization of genetic material inside the cell?
A.
chromosomes → nucleus → genes → DNA
B.
DNA → genes → nucleus → chromosomes
C.
genes → DNA → chromosomes → nucleus
D.
nucleus → DNA → gene → chromosomes
Answer:
A
Explanation:
I got it in a test
(89 point )Use the diagram to determine the difference between freezing rain and sleet. (Freezing rain melts in warm air and then freezes on cold surfaces while sleet refreezes before it hits the surface of Earth) ( Sleet is wet and rain is frozen) (Freezing rain melts in warm air then refreezes before it reaches the surface, while sleet falls wet and freezes on the surface) don't get me just the answer. give me poof
Answer:
it is actually 45 points
Explanation:
Freezing rain melts in warm air and then freezes on cold surfaces while sleet refreezes before it hits the surface of Earth. Sleet is wet and rain is frozen. Freezing rain melts in warm air then refreezes before it reaches the surface, while sleet falls wet and freezes on the surface. you basically wrote out your answer yourself and you´re proof, i gooogled it, lol
Answer:
Freezing rain melts in warm air and then freeze then refreeze before it reaches the surface
Calculate the wavelength of radiation with a frequency of 4.9 ×1014 per second.
Answer in units of meters.
The wavelength-λ = 6.12 x 10⁻⁷ m
Further explanationRadiation energy is absorbed by photons
The energy in one photon can be formulated as
[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]
Where
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves
f = c / λ
c = speed of light
= 3.10⁸ m/s
λ = wavelength
The wavelength of radiation with a frequency of 4.9 ×10¹⁴/s :
[tex]\tt \lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3.10^8}{4.9\times 10^{14}}\\\\\lambda=6.12\times 10^{-7}~m[/tex]
What could cause the Earth's crust to become a liquid?
Answer:
Oceanic crust, extending 5-10 kilometers (3-6 kilometers) beneath the ocean floor, is mostly composed of different types of basalts. Geologists often refer to the rocks of the oceanic crust as “sima.” Sima stands for silicate and magnesium, the most abundant minerals in oceanic crust. (Basalts are a sima rocks.) Oceanic crust is dense, almost 3 grams per cubic centimeter (1.7 ounces per cubic inch).
Oceanic crust is constantly formed at mid-ocean ridges, where tectonic plates are tearing apart from each other. As magma that wells up from these rifts in Earth’s surface cools, it becomes young oceanic crust. The age and density of oceanic crust increases with distance from mid-ocean ridges.
Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones. Subduction is the important geologic process in which a tectonic plate made of dense lithospheric material melts or falls below a plate made of less-dense lithosphere at a convergent plate boundary.
At convergent plate boundaries between continental and oceanic lithosphere, the dense oceanic lithosphere (including the crust) always subducts beneath the continental. In the northwestern United States, for example, the oceanic Juan de Fuca plate subducts beneath the continental North American plate. At convergent boundaries between two plates carrying oceanic lithosphere, the denser (usually the larger and deeper ocean basin) subducts. In the Japan Trench, the dense Pacific plate subducts beneath the less-dense Okhotsk plate.
Explanation:
are Li, Na and K in the same group
Answer: Yes, they are.
Explanation:
Yes, they are. Li, Na, and K are referring to Lithium, sodium, and potassium.
They are all belonging to the same group which is called the alkali metals group.
They are having the same number of valence electrons i.e. 1.
This group of the alkali metals are considering tree more metals in it which are Rb, Cs, and Fr.
WHEN A SOCCER PLAYER KICKS A BALL, THE BALL ACCELRATES. EXPLAIN WHAT CAUSES THIS ACCELERATION IN TERMS OF FORCES?
EXPLAIN WHAT HAS A GREATER INERTIA- A SPEEDING CAR OR A JET AIRPLANE SITTING ON A RUNWAY.
DO FORCES ALWAYS CAUSE MOTION? EXPLAIN
DESCRIBE THREE EXAMPLES FROM SPORTS IN WHICH A FORCE CHANGES HE VELOCITY OF AN OBJECT OR A PERSON.
Answer:
When we kick the ball, the force we apply to it causes it to accelerate from a speed of 0 to a speed of dozens of kilometers per hour. When the ball is released from the foot, it begins to decelerate (negative acceleration) due to the force of friction that is exerted upon it (as we observed in the previous example).
Explanation:
Which of these statements describes the basic idea of the Valence Shell
Electron Pair Repulsion (VSEPR) theory?
1. Molecules repel one another due to intermolecular forces.
2. There is always an octet of electrons around an atom in a molecule
3. Shared and unshared electron pairs repel each other as much as
possible
4. Electrons are attracted to the nucleus of the central atom.
Answer:
3. Shared and unshared electron pairs repel each other as much as
possible
Explanation:
The variations in the bond angles of molecules and ions can be explained using the valence shell electron pair repulsion theory.
The VESPR model determines the total number of electron pairs (TEP) surrounding the central atom of a specie. The TEP consists of bond pairs BP and lone pairs LP.
All the electron pairs will orient themselves in such a way as to minimize the electrostatic repulsion between them.
The repulsion determines the geometry of the covalent bonds around the central atom. As the number of lone pairs increases from 0 to 2, the bond angles diminishes progressively.
*please be serious *
What is one way active transport is different from diffusion ?
Answer:
Explanation:
During active transport, molecules move from an area of low concentration to an area of high concentration. This is the opposite of diffusion, and these molecules are said to flow against their concentration gradient.
at the left.
6.
1. Work equals
A force x distance
B. force - distance
C. force + distance.
The force you apply to a machine
is the
A. input force.
B. output force.
C. efficiency.
2.
The unit of work is the
A. watt.
B. newton.
C. joule.
7.
The efficiency of all real
machines is
A. greater than 100%
B. equal to 100%
C. less than 100%
3.
Power is the amount of
A. work done per unit of time.
B. force on a certain area.
C. pressure in a volume of liquid.
8.
4.
The unit for power is the
A. joule.
B. Meter per second
C. watt.
The fixed point that a lever rotates
around is called the
A. fulcrum.
B. input force.
C. wedge.
9.
5.
A machine cannot change the
A. direction of the input force.
B. amount of work needed to do
A screwdriver is an example of a
simple machine called a
A. pulley.
B. screw
C. wheel and axle.
a task.
C. distance over which a force
is applied
10.
Your front teeth are
A. wedges.
B. levers.
C. compound machines.
Answer:
i know right answer
Explanation:
let me explain
Which of the following sets of descriptors matches the molecule below?
Image of two oxygen atoms bonded together to form O2.
A. Compound, allotrope, double bond, one element
B. Molecule, compound, single bond, allotrope
C. Simple structure, diatomic, double bond, molecule
D. Giant structure, single bond, compound, one element
Simple structure, diatomic, double bond, molecule. Hence, option C is correct.
What is a compound?A pure substance made up of two or more different elements combined chemically in a fixed ratio is called a compound.
[tex]O_2[/tex] is a covalent molecule because each oxygen atom needs two valence electrons to complete its octet. To meet this need each oxygen atom shares two of its electrons with the other oxygen forming a strong oxygen-oxygen double-shared covalent bond.
Hence, option C is correct.
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