Answer:
the correct answer is option ( A )
Both A and R are true and R is the correct explanation of A.
Explanation:
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Which of the following are true for an element? (i)Atomic number= number of protons + number of electrons (ii)Mass number = number of protons+ number of neutrons (iii)Atomic mass= number of protons= number of neutrons (iv)Atomic number = number of protons = number of electrons
Answer:
ii and iv
Explanation:
atomic mass is the sum of protons and neutrons
protons ( postively charged) usually have the same number like electrons( negatively charged)
Which of the following about a balanced chemical reactions is
NOT true?
O A properly written chemical equation will include the states of matter
for every substance in the reaction.
O The number of atoms of each element must be the same for both
reactants and products.
A balanced chemical equation must follow the Law of Conservation
of Matter
A balanced chemical equation must always include coefficients on
every reactant and product.
Answer:
A balanced chemical equation must always include coefficients on every reactant and product.
Explanation:
A balanced chemical equation does not need to include coefficients on every reactant and product.
For example, below is a balanced chemical equation in which the reactants and the products have no coefficients whatsoever:
NaOH(aq) + HCl (aq) -----> NaCl (s) + H2O (l)
Of course, a properly written chemical equation must include the states of matter of all the substances in the reaction and the number of atoms of each element must balance both in the reactant and product sides of the equation. Generally, a balanced chemical equation must obey the law of conservation of matter which opines that matter can neither be created nor destroyed but can only be converted from one form to another.
Hence, that a balanced chemical equation must always include coefficients on every reactant and product is not true.
If a quantity of this substance existed as a solid at a pressure of 0.75 atm and a temperature of 50°C, what phase
change(s) would occur if the temperature increased to 500°C?
a. Freezing and deposition
b. Melting and freezing
c. Condensation and sublimation
d. Melting and vaporization
Element 'X' forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:
I) Si
2) Al
3) Mg
4) Na
pls pls answer fast
Answer:
Mg
Explanation:
Mg forms 2+ ions and mgcl2 has a melting point over 700°C I believe.
PLZ HELL ME WITH MY WORK
Answer:
Ba
Explanation:
1. Necesitas un "cubo concentrado" (de esos que se usan para sazonar las comidas Maggie, ricostilla) dos vasos de vidrio o plástico y agua (caliente y fría). 2.Agrega al vaso con agua fria la mitad de un cubo concentrado y déjala reposar unos minutos. Prepara el segundo vaso con agua caliente y agrégale la otra mitad del cubo. 3. Argumenta tus observaciones en relación con lo observado y con la teoria vista. ¿Como influye la temperatura en este experimento?
plz answer (d) explain
Cu2+ is reduced to Cu.
Change in oxidation state is from +2 to 0
Describe how you would prepare a supersaturated solution
Answer:
A supersaturated solution contains more dissolved solute than required for preparing a saturated solution and can be prepared by heating a saturated solution, adding more solute, and then cooling it gently. Excess dissolved solute crystallizes by seeding supersaturated solution with a few crystals of the solute.
Explanation:
Cual es la longitud de onda de un foton emitido durante la transicion desde el stado n=5 al estado n=3 en atomo Hidrogeno? Dar como respuesta de la longitud de onda en nm (nanometros)
Answer:
1302 nm
Explanation:
Del formulario de Rydberg para longitud de onda
1 / λ = R (1 / nf ^ 2 - 1 / ni ^ 2)
1 / λ = 1.097 × 10 ^ 7 (1/3 ^ 2 - 1/5 ^ 2)
1 / λ = 1.097 × 10 ^ 7 (0.11 - 0.04)
1 / λ = 1.097 × 10 ^ 7 (0.07)
= 1,302 × 10 ^ -6 m
o 1302 nm
Calculate the mass percent of carbon,oxygen, nitrogen and hydrogen in acetamide, C2H5NO.
Molar Mass:
O=16, N=14,C=12, H =1.
Answer:
40.68 % C
23.73 % N
8.47% H
27.12% O
Explanation:
The mass percent of an element X in a compound is calculated as the molar mass (MM) of X multiplied by the number of atoms of X in the compound, divided into the molecular weight (MW) of the compound, as follows:
mass percent of X = (MM(X) x number of atoms of X)/MW compound x 100
Thus, we first calculate the MW of acetamide (C₂H₅NO) by using the molar mass of the chemical elements C, H, N and O:
MW(C₂H₅NO) = (12 g/mol C x 2) + (1 g/mol H x 5) + 14 g/mol N + 16 g/mol O = 59 g/mol
Now, we can calculate the mass percent of each element (C, H, N, O) in C₂H₅NO:
Mass percent of C (2 atoms of C in 1 molecule of C₂H₅NO):% mass C = (12 g/mol x 2)/(59 g/mol) x 100 = 40.68 %
Mass percent of N (1 atom of N in 1 molecule of C₂H₅NO):% mass N = (14 g/mol x 1)/(59 g/mol) x 100 = 23.73 %
Mass percent of H (5 atoms of H in 1 molecule of C₂H₅NO):
% mass H = (1 g/mol x 5)/(59 g/mol) x 100 = 8.47 %
Mass percent of O (1 atom of O in 1 molecule of C₂H₅NO):
% mass O = (16 g/mol x 1)/(59 g/mol) x 100 = 27.12 %
The sum of the mass percents has to be equal to 100%:
40.68 % C + 23.73 % N + 8.47% H + 27.12% O = 100%
Name the following compound NiBr2?
Answer:
the Name of NiBr2 is
Nickel(II) bromide
Identifica las formas de energía mecánica
(cinética y potencial) que tienen lugar en diferentes puntos del movimiento en
un sistema mecánico (caída libre, montaña rusa, péndulo).
2 Tipos de Energía Mecánica
2.1 1. Energía hidráulica
2.2 2. Energía eólica
2.3 3. Energía Mareomotriz
3 Ejemplos de Energía Mecánica
3.1 1. Planta hidroeléctrica
3.2 2. Máquinas de Vapor
3.3 3. Motor de Combustión interna
3.4 4. Molinos de Viento
3.5 5. Un Juego de Billar
3.6 6. Motor eléctrico
3.7 7. Locomotora
3.8 8. Bala
3.9 9. Una pistola de Dardos
3.10 10. Pelota sobre una mesa
https://www.aura-energia.com/ejemplos-de-energia-mecanica/
An unknown compound has the following chemical formula: NxO
where x stands for a whole number.
Measurements also show that a certain sample of the unknown compound contains 5.2 mol of nitrogen and 2.65 mol of oxygen
Write the complete chemical formula for the unknown compound.
Taking into account the definition of empirical formula, the complete chemical formula for the unknown compound is N₂O.
The empirical formula of a chemical compound shows the ratio between the atoms of the compound. That is, it indicates which elements are present and the minimum ratio in whole numbers between their atoms. The empirical formula is the simplest chemical formula for a chemical compound, which is why it is also called the minimum formula.
The empirical formula must be expressed using integer relationships, then to obtain this formula, divide the numbers of moles by the smallest result of them. In this case:
Nitrogen: [tex]\frac{5.2 moles}{2.65 moles}[/tex]= 1.96 moles ≅ 2 moles
Oxygen [tex]\frac{2.65 moles}{2.65 moles}[/tex]= 1 mole
Being the chemical formula of hte compound NxO, where x stands for a whole number, this indicates that the elements N and O are in the compound in a whole number ratio of x: 1. Then, as in the empirical formula, the numbers of moles must be expressed in whole numbers, as previously calculated, the value of x must be 2.
In summary, the complete chemical formula for the unknown compound is N₂O.
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Which statement describes the "Law of Conservation of Mass" for the following reaction?
4 Fe + 302 -
2 Fe₂O₃
Select one:
tion
a.
grams of Fe + grams of Fe2O3 = grams of O2
O b. grams of O2 + grams of Fe2O3 = grams of Fe
O c. grams of Fe +grams of O2 = grams of Fe203
O d. None of these.
Name this ionic compound.
Answer:
c
Explanation:
The intermediate product formed during the production of urea is,
Answer:
Arginine is intermediate product formed during the production of urea
The key combination is ornithine, on which the urea molecule is 'created'; intermediates in the procedure contain citrulline and arginine.
What is the Production of Urea?
The urea cycle is a procedure of conversion of toxic ammonia to negligibly toxic urea. Consequences of the urea cycle are 1 molecule of urea, 2 molecules of ADP, and 1 molecule of both AMP and fumaric acid.
When Ammonia and carbon dioxide recovery During urea decomposition a mixture of gaseous carbon dioxide and also ammonia is accumulated and also immersed into a dilute aqueous urea resolution.
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Which of the following processes does NOT facilitate containment?
Answer:
b is the answr
Explanation:
The correct answer is Option (B) Enrichment of Uranium-235 is done.
What is Containment? Containment is the process of preventing pollution or contamination of the immediate site environment by dust, chemicals, and other materials to prevent corrosion.What is Corrosion?Corrosion is a natural process that converts a refined metal into a more chemically stable oxide.The degree of containment is directly proportional to the degree of toxicity present in the corrosion preventive substance being applied.Why other options are incorrect?Option (A) , (C) , (D) are the options that facilitate containment because these are the processes for preventing contamination.
Hence Option (B) is correct because enrichment of uranium-235 is achieved by the process of conversion So , It does not facilitate containment
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It's said that not all electrons in an atom have the same amount of energy. Is it the same for protons? Because if it's not then how come they have the same atomic number at the end?
Answer:
When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.
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For the reaction 2A + 4B ----> 2C + 2D, at a particular instant in time, the rate of the reaction is 0.0352 M/s. What is the rate of change of B? Show Work!
A. 0.0088 M/s
B. -0.0088 M/s
C. -0.141 M/s
D. -0.0352 M/s
E. 0.141 M/s
Explanation:
The given chemical equation is:
[tex]2A + 4B -> 2C + 2D[/tex]
The rate of the reaction is 0.0352 M/s.
During the course of the reaction, the rate of reactants decreases, and the rate of products increases.
The rate of disappearance of B is shown below:
[tex]rate=-\frac{1}{4} \frac{d[B]}{dt}[/tex]
So, rate of change of B is :
[tex]rate of change of B =- rate * 4\\=-0.0352 M/s * 4\\=-0.1408M/s\\\\=-0.141M/s[/tex]
Option C.
In the given reaction, rate of change of reactant B is equal to -0.141 M/s.
What is the rate of reaction?Rate of any chemical reaction defines the speed of the completion of that reaction.
In the question given reaction is:
2A + 4B ----> 2C + 2D
Rate of reaction = 0.0352 M/s.
Rate of the reaction with respect to the reactant B is written as:
Rate = [tex]${\rm{ - }}\frac{{\rm{1}}}{{\rm{4}}}\frac{{\left[ {{\rm{dB}}} \right]}}{{{\rm{dT}}}}$[/tex], where negative sign shows the disappearance of reactant B.
Rate of change of B i.e. [tex]$\frac{{{\rm{dB}}}}{{{\rm{dT}}}}$[/tex] = 4 × (-rate)
[tex]$\frac{{{\rm{dB}}}}{{{\rm{dT}}}}$[/tex] = 4 × (-0.0352) = -0.1408 = -0.141 M/s
Hence, -0.141 M/s is the rate of change of B.
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A process which is unfavorable with respect to enthalpy, but favorable with respect to entropy Group of answer choices could occur at high temperatures, but not at lower temperatures. could not occur regardless of temperature. could occur at any temperature. could occur at low temperatures, but not at higher temperatures. none of the above
Answer:
could occur at any temperature.
Explanation:
The spontaneity of a reaction is what determines whether the reaction will occur or not. A spontaneous reaction occurs easily.
The spontaneity of a reaction is predicted by the sign of ∆G.
When ∆G is positive, the reaction is not spontaneous. When ∆G is negative, the reaction is spontaneous.
Note that;
∆G= ∆H - T∆S
Where;
∆H = Change in enthalpy
∆S = Change in entropy
T= temperature
If ∆H is unfavourable and ∆S is favourable, the reaction can proceed at all temperatures because ∆G will always be negative.
It should be noted that a process that is unfavorable as regards to enthalpy, but favorable with respect to entropy could occur at any temperature.
Enthalpy(∆H) serves as amount of internal energy that a compound has, entropy( ∆S) on the other hand serves as intrinsic disorder within the system.
However, spontaneity of a reaction determines likely hood of occurrence of a reaction, when the process is spontaneous, it makes the reaction to occurs easily.
We can conclude that whenever enthalpy is unfavourable and entropy of a system is favourable, then the spontaneity will be negative and the reaction will occur at any temperature.
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use the the dot strict on the right to and the periodic table to determine the element represented.
sodium (Na)
potassium (K)
neon (Ne)
argon (Ar)
Answer:
Pottasium
Explanation:
because it is the nineteenth element
Answer:
The answer is B. Potassium.
Explanation: Potassium has 19 electrons that are organized like the image if you count the electrons on each obital. This answer is correct on edge 2020. Hope this helps!
A liquid that occupies a volume of 8.2L has a mass of 5.6kg. What is the density of the liquid in kg/L
Answer:
0.68
Explanation:
This is because the formula for finding density is mass/volume. Therefore the equation becomes 5.6/8.2 giving you 0.68
Brainliest if answered correctly
How many Calcium (CA) atoms are in carbon tetrachloride
Answer:
What atoms are present in carbon tetrachloride?
There is 1 carbon, and 4 chlorine atoms (or chloride ions if you want to get technical). Tetra means 4 in Greek.
hope that helps❤
Answer:
there are no calcium atoms of n carbon tetrachloride
Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once.
While picking up a buret, an unknown solution left by a previous solution drips onto your hand._______________
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor _______
While checking on a stirring solution, the solution splashes up towards your face. _______
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench, __________
A. Gloves
B. Lab coat
C. Goggles
D. Closed-toe shoes
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
Explanation:
The full form of PPE is 'Personal Protective Equipment'.The PPE items we use in labs are : Lab coat: Protection of clothing and skin from accidental spilling of hot liquid or toxic substances. Gloves: Protection from hands from chemicals, hot objects, sharp tools, or electricityGoggles: Protection of the eye from any chemicals, toxic vapor, chemical debrisFace shield: Protection of the face from any chemicals, toxic vapor, chemical debrisClosed-toe shoes: Protection from feet from chemicals, hot objects, sharp tools, or electricitySo, according to the question. the matches will be:
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
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2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions.
Answer:
The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other
The compounds formed includes;
1) Nitric oxide, NO
Nitrogen = 46.66% × 30.01 = 14
Oxygen = 53.34% × 30.01 = 16
2) Water, H₂O
Hydrogen = 11.21% × 18.01528 = 2
Oxygen = 88.79% × 18.01528 ≈ 16
3) Ammonia, NH₃
Hydrogen = 17.78% × 17.031 ≈ 3
Nitrogen = 82.22% × 17.031 ≈ 14
The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8
The ratio of nitrogen to hydrogen in ammonia = 14:3
The ratio in which hydrogen and oxygen combine with nitrogen = 3/16
The ratio of hydrogen and oxygen combine with each other in water = 2/16
Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions
Explanation:
BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change
Answer:
1.Physical change
2. Chemical change
3. Heat
4.photosynthesis
5. composition
Using dobereiner's triads, what conclusion could have been made about magnesium
Answer:
Triads were groups of 3 elements with similar chemical and physical properties. Beryllium, magnesium, and calcium are all earth alkalis found in the earth
Explanation:
Name five metal which are both dilute and memorable? class 10
Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.
Answer:
29.41% of Calcium and 47.04% of Oxygen
Explanation:
The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.
The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:
13.61g / 46.28g * 100 = 29.41% of Calcium
And percent composition of Oxygen is:
21.77g / 46.28g * 100 = 47.04% of Oxygen
how do i calculate the concentration of a certain solution
Answer:
Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.
Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu
Answer:
132.17amu
Explanation:
(14.01+1.01 multiplied by 4)=18.05×2=36.1
36.1+32.07= 68.17
16.00×4=64
68.17+64=132.17
Answer:
132.17 amu
Explanation:
just took the test. got 100
