Answer:
This statement is the definition of law of conservation of mass.
Explanation:
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
For example:
In given photosynthesis reaction:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.
Let us consider the general chemical reaction.
A + B → C
5g + 5g 10g
Convert 5.4g of NaCl to moles
Answer:
.0924 moles of NaCl
Explanation:
So you know you have 5.4 g of NaCl and you need to know how many moles there are in this amount of NaCl
You'll need to find the atomic mass of the compound NaCl to help you solve for moles Sodium (Na) on the periodic table has a mass of 22.99 Chlorine (Cl) on the periodic table has a mass of 35.45Add these two together----> 22.99 + 35.45 = 58.44
Now you can calculate for moles
Written-out method:
5.4 grams of NaCl | 1 mole of NaCl
| 58.44 grams NaCl = .0924 moles of NaCl
Plug into calculator method:
(5.4 g of NaCl/ 58.44g NaCl= .0925 moles)
Which phrase is not an example of intercellular communication?
A chemical messengers dock onto receptors of adrenal gland
B chemical signal from pituitary gland to adrenal gland
C electrical signals pass between heart cells
D a vesicle encloses over a nutrient molecule
Answer: The answer is D
Explanation: I took the quiz just now and got it right
The correct answer is:
D.(a vesicle encloses over a nutrient molecule)
I took the test, hope this helps!
When iron reacts with oxygen, it forms iron oxide, or rust.
4 Fe + 3 O2 2 Fe2O3
If 112 g of iron (Fe) combines with 24 g of oxygen (O2), how much iron oxide is formed?
Answer:
Mass of iron oxide: 79.85 g
Explanation:
Given data:
Mass of iron = 112 g
Mass of O₂ = 24 g
Mass of iron oxide formed = ?
Solution:
4Fe + 3O₂ → 2Fe₂O₃
Number of moles of Fe:
Number of moles = mass/ molar mass
Number of moles = 112 g/ 55.85 g/mol
Number of moles = 2 mol
Number of moles of O₂:
Number of moles = mass/ molar mass
Number of moles = 24 g/ 32 g/mol
Number of moles = 0.75 mol
Now we will compare the moles of oxygen and iron with iron oxide.
Fe : Fe₂O₃
4 : 2
2 : 2/4×2 = 1
O₂ : Fe₂O₃
3 : 2
0.75 : 2/3×0.75 = 0.5
The number of moles of iron oxide formed by oxygen are less thus it will be limiting reactant.
Mass of iron oxide:
Mass = number of moles × molar mass
Mass = 0.5 mol × 159.69 g/mol
Mass = 79.85 g
Answer:
136 g Fe2O3
Explanation:
study island
based on the half-life of Tc-99, how many half-lives have to pass for a 150 mg sample of Tc-99 to decay down to 30mg?
Answer:
2.322 half-lives have passed to decay down from 150 miligrams to 30 miligrams.
Explanation:
The half of Technetium-99 is approximately 211000 years. The decay of isotopes is represented by the following ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)
Where:
[tex]\frac{dm}{dt}[/tex] - First derivative of isotope mass in time, measured in miligrams per year.
[tex]m[/tex] - Mass of the isotope, measured in miligrams.
[tex]\tau[/tex] - Time constant, measured in years.
Now we proceed to obtain the solution of this differential equation:
[tex]\frac{dm}{m} = -\frac{dt}{\tau}[/tex]
[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]
[tex]\ln m = -\frac{t}{\tau}+C[/tex]
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)
Where:
[tex]m_{o}[/tex] - Initial mass of the isotope, measured in miligrams.
[tex]t[/tex] - Time, measured in years.
The time passed for isotope is cleared within the equation described above:
[tex]\ln \frac{m}{m_{o}} = -\frac{t}{\tau}[/tex]
[tex]t = -\tau \cdot \ln \frac{m}{m_{o}}[/tex]
In addition, we can obtain the time constant as a function of half-life:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)
If we know that [tex]t_{1/2} = 211000\,yr[/tex], [tex]m_{o} = 150\,mg[/tex] and [tex]m = 30\,mg[/tex], then the time passed is:
[tex]\tau = \frac{211000\,yr}{\ln 2}[/tex]
[tex]\tau \approx 304408.654\,yr[/tex]
[tex]t = -(304408.654\,yr)\cdot \ln \left(\frac{30\,mg}{150\,mg} \right)[/tex]
[tex]t \approx 489926.829\,yr[/tex]
The amount of passed half-lives is that time divided by a half-life. That is:
[tex]n = \frac{489926.829\,yr}{211000\,yr}[/tex]
[tex]n = 2.322[/tex]
2.322 half-lives have passed to decay down from 150 miligrams to 30 miligrams.
What do we call the study of matter and how matter changes?
Answer:
Explanation:
Chemistry is the study of matter and the changes that matter undergoes. Matter is anything that has mass and takes up space.
5. Explain why the particle diagram below represents a chemical change.
plsss help!!!
Answer:
the atoms are rearranged
Explanation:
they are just in a diff order
The particle diagram represents a chemical change because the breaking of old chemical bonds and the formation of new chemical bonds occurs and a completely new substance is formed.
What is the chemical change?A chemical change is when a chemical substance is completely transformed into one or more different types of substances. Chemical changes occur through chemical reactions and result in substances with different and new chemical and physical properties.
Chemical changes are irreversible in nature and are also known as permanent changes. When chemical responses occur, the molecules are modified and joined by an energy change as new molecules are produced.
Examples of chemical changes: burning of coal, rusting of iron, digestion of food, adding vinegar to baking soda, germination of seeds, ripening of fruits, cooking an egg, etc.
The given diagram is quite similar to the water formation reaction:
2H₂ + O₂ [tex]\longrightarrow[/tex] 2H₂ O
In which the bond between the hydrogen atoms and oxygen atoms is broken and the formation of the O-H bond, therefore, is a chemical change.
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What is epithelial tissue characterized by?
closely packed cells
sarcomeres
many cell junctions
an extracellular matrix
Answer:
closely packed cells
many cell junctions
Explanation:
Answer:
A,B
Explanation:
EDGE2021
18. Which of these is an ion?
A. Fluorine with 9 protons
B. Calcium with 18 electrons
C. Calcium with 18 neutrons
D. Fluorine with 9 neutrons
which statement differentiates between prokaryotic cells and eukaryotic cells?
A.Eukaryotic cells have DNA: prokaryotic cells do not.
B. Prokaryotic cells have DNA: eukaryotic cells do not.
C. Eukaryotic cells have nuclei: prokaryotic cells do not.
D. Prokaryotic cells have nuclei: eukaryotic cells do not.
Answer:
It is C
Explanation:
It is because Prokaryotic cells mostly don't have a nucleus.
Answer:
It is C.Eukaryotic cells have nuclei; prokaryotic cells do not
Explanation:
I just watched a video of it.
What is conduction?
Transfer of heat through circular movement
Transfer of heat through direct physical contact
Transfer of heat through electromagnetic waves
Transfer of heat through the movement of part
Answer:
Transfer of heat through direct physical contact
Explanation:
The meaning of conduction is the transfer of heat directly transmitted through a substance when there is the difference between temperature and electrical potential. Hope it helps!
Answer:
B
Explanation:
an atom has 79 protons, 78 electrons and a mass number of 118. how many neutrons does this atom have
Answer:
39
Explanation:
Electrons weigh almost nothing, so their mass doesn't really matter for these types of problems. Just subtract 118-79 to find the remaining mass which is for the neutrons.
While looking at calcium (Ca) on the periodic table, a student needs to find an element with a greater atomic mass in
the same period. Where should the student look?
O directly up
O directly down
O directly to the left
O directly to the right
Answer:
D. Directly to The Right
Calculate the atomic mass of the unknown element X described below.
Please help
Answer:
286
Explanation:
Add atomic mass of all the Isotopes,
Outcome = 825
divide it by number of isotopes which is 4 because there are 4 isotopes
Atomic mass of x = [tex]\frac{825}{4}[/tex]
Atomic mass of x is 286
The atomic mass of the unknown element X is 206 amu. Thus option B is correct.
What is atomic mass?Atomic mass is defined as the relative mass of the element's atom in comparison to the mass of an atom of the C12 isotope.
In an example, the general atomic mass is the average of the atomic masses of a large number of different isotopes.
First we added atomic mass of each isotopes
= 204 + 206 + 207 + 208 = 824
Now to calculate the atomic mass of element X we divide it by 4 as there is four isotopes
So, atomic mass = 824 / 4
= 206 amu
Thus, the atomic mass of the unknown element X is 206 amu. Thus option B is correct.
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PLS HELP ITS URGENT
Some plant cells need energy to carry nutrients across the cell membrane. Which type of energy transformation does these plant cells use to bring the nutrient molecule inside the cell membrane?
thermal energy to kinetic energy
potential energy to light energy
chemical energy to kinetic energy
kinetic energy to potential energy
Answer:
Answer
The answer is option 4
The energy transformation during nutrients transportation across the cell membrane is transformation from chemical energy to kinetic energy, where the uphill and downhill movements of molecules based on concentration gradient carries the whole process.
What is energy transformation?The total energy in a system is always conserved. However, one form of energy can be transformed into another form. For example we uses electrical devices such as bulbs fan etc, wherever the energy transformation is getting way from electrical energy to light or mechanical energy.
In plant cells nutrient molecules and ions are balanced inside and outside the cell and hence they are transported across the cell membrane by a concentration gradient with a chemical energy produced by the molecules.
The chemical energy inside of the ions and molecules converts to kinetic energy to transport itself through downhill and uphill mechanisms with aid of various enzymes and electron channels.
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If 116 g of butane burns in the presence of 320. g of oxygen how much carbon dioxide will be produced? CO2 produced in grams
Answer:
270.77 g of CO2.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2C4H10 + 13O2 —> 8CO2 + 10H2O
Next, we shall determine the masses of C4H10 and O2 that reacted and the mass of CO2 produced from the balanced equation. This can be obtained as follow:
Molar mass of C4H10 = (12×4) + (10×1)
= 48 + 10 = 58 g/mol
Mass of C4H10 from the balanced equation = 2 × 58 = 116 g
Molar mass of O2 = 2 × 16 = 32 g/mol
Mass of O2 from the balanced equation = 13 × 32 = 416 g
Molar mass of CO2 = 12 + (16×2)
= 12 + 32 = 44 g/mol
Mass of CO2 from the balanced equation = 8 × 44 = 352 g
Summary:
From the balanced equation above,
116 g of C4H10 reacted with 416 g of O2 to produce 352 g of CO2.
Next, we shall determine the limiting reactant. This can be obtained as follow:
From the balanced equation above,
116 g of C4H10 reacted with 416 g of O2.
From the above, we can see that a higher mass of O2 i.e 416 g than what was given i.e 320 g his needed to react completely with 116 g of O2. Therefore, O2 is the limiting reactant and C4H10 is the excess reactant.
Finally, we shall determine the mass of CO2 produced from the reaction.
In this case, we shall use the limiting reactant because it will give the maximum yield of CO2.
The limiting reactant is O2 and the mass of CO2 produced can be obtained as follow:
From the balanced equation above,
416 g of O2 reacted to produce 352 g of CO2.
Therefore, 320 g of O2 will react to produce = (320 × 352)/416 = 270.77 g of CO2.
Thus, 270.77 g of CO2 were obtained from the reaction.
A piece of metal is composed of atoms. Each atom in the metal contains 29 protons. How is the metal classified?
Answer:
The metal is Copper
Explanation:
Matter is composed of atoms, which is the smallest indivisible particle of an element. The atom of an element consists of three subatomic particles namely: proton, electron and neutron etc.
The proton, which is the positively charged particle, is equal to the electron, which is the negatively charged particle. The proton number of the atom is the ATOMIC NUMBER of an element.
In the periodic table, the element with atomic number 29, which also means proton number 29 is Copper (Cu).
how many moles in 1.505x10^23 Na atoms
Answer:
The answer is 0.25 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
N = 1.505 × 10²³ Na atoms
We have
[tex]n = \frac{1.505 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{1}{4} \\ [/tex]
We have the final answer as
0.25 molesHope this helps you
An object with a mass of 15 kg has an acceleration of 3 m/s/s. What is the force
applied to the object? *
45 N
5N
18 N
Answer:
45N
Explanation:
force=mass×acceleration
Help me lol
I’ll give branliest if two people answer
Answer:
I think all of the above
Explanation:
Put as brainliest if you wish
Ok here is the next one
I’m counting on you
Thanks.
food moves through the mouth by muscle movement
what is the chemical formula for the magnesium ion and the carbonate ion?
Answer: The formula for magnesium carbonate is MgCO_3.
Explanation:
Mass can be changed into energy in a ____ reaction
A)Chemical
B)Nuclear
How many elements are in H2CrO4
Answer:
3 elements
Explanation:
The elements are:
- Chromium
- Hydrogen
- Oxygen
HEEELLLPPPP:(!!!!! im stuckkkk!!!
Answer:
LIGHT
AIR
SHELTER
FOOD
WATER
Answer:
light
air
shelter
food
water
What was the average speed of the truck for this trip?
A solution that holds more solute than it normally can under the conditions at a given temperature is _____. supersaturated unsaturated saturated diluted
Answer:
Supersaturated !
Explanation:
2. How does friction effect speed?
Answer:
It acts as a force upon it like in newtons first law of motion an object in motion will stay in motion until a force acts upon it So friction bascicallly slows it down or stops it completly
Explanation:
I WILL MARK YOU THE BRANLIEST!!!
Which property shows that electrons are quantized?
A. Electrons are attached to protons.
B. Each electron has its own "address."
C. Each electron carries a charge.
D. Electrons have very little mass.
Answer:
B. Each electron has its own "address."
Explanation:
This is the correct answer.
Good luck with the rest, and have a good day : )
Each electron has its own "address." Therefore, the correct option is option B among all the given options.
What is quantization?The elementary electric charge of the electron is a negative one, making it a subatomic particle. Due to their lack of components or substructure, electrons, which are part of the lepton particles family's first generation, are typically regarded to be elementary particles. The mass of an electron is roughly 1/1836 that of a proton.
The electron has a half-integer intrinsic rotational momentum that is represented in terms of the decreased Planck constant,, among its quantum mechanical features. The rule of exclusion developed by Pauli states that because electrons are fermions, no two of them may be in the same quantum state. Since they're capable of collide against other particles as well as can be bent like light, electrons, like all primary particles, display both wave and particle characteristics. Each electron has its own "address."
Therefore, the correct option is option B.
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How would I create a Lewis dot structure with the compound: CHBr2Cl
Answer:
Step 1: Find the Total Number of Valence Electrons. ...
Step 2: Find the Number of Electrons Needed to Make the Atoms "Happy" ...
Step 3: Determine the Number of Bonds in the Molecule. ...
Step 4: Choose a Central Atom. ...
Step 5: Draw a Skeletal Structure. ...
Step 6: Place Electrons Around Outside Ato
Explanation:
Which statements about exothermic and endothermic reactions are correct? (its a multiple choice question)
1 During an exothermic reaction, heat is given out.
2 The temperature of an endothermic reaction goes up because heat is taken in.
3 Burning methane in the air is an exothermic reaction.
A) 1.2 and 3
B) 1 and 2 only
C) 1 and 3 only
D) 2 and 3 only
Answer:
C)1 and 3 only☺️
Explanation: