Answer: B
Explanation:
I. Rusting is a chemical reaction which is oxidation of iron.
II. Boiling water is a physical change. There is no chemical change between H2O molecules. It only shifts to the gas state from the liquid state.
III. When egg is cooked proteins are denaturated so it changes interactions between molecules.
IV. Melting is also just a phase change like boiling.
WHICH STATEMENT BEST REPRESENTS A HYPOTHESIS
Answer:
D
Explanation:
Hypotheses are educated guesses, and the best answer is the one with an if, as it indicates that it's a guess.
Answer:
letter b should be the answer
Uranium-235 and uranium-238 are different ________ of uranium
(Apx answers please)
Answer:
Isotopes
Explanation:
An isotope are the atoms of an element with similar chemical identity and number of protons but different atomic masses. This means that isotopes of an element differ from one another by their number of NEUTRONS.
For example, the uranium element possesses isotopes as follows: Uranium-235 and uranium-238. This two isotopes have the same chemical identity and number of protons/atomic no., which is 92. However, the atomic masses (235 and 238) are different.
Answer:
Isotopes
Explanation:
Formation of HCl from H₂and Cl₂ is example of
photochemical
electrochemical
displacement
Answer:
Combination reaction.
Explanation:
The reaction depicted in the question is;
H2 (g) + Cl2 (g) ⟶ 2HCl (l)
Now, this reaction shows that two reactants namely hydrogen and chlorine react to form a single product named Hydrogen chloride. This process is called combination reaction.
the element of group 1 are reactive but those of group 18 are inert, why
Answer:
Because elements of group 1 does not have stable electronic configuration and elements of group 18 have stable electronic configuration.
Explanation:
Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.
What are the element of group 1?Group 1 elements contain the alkali metals, Li, Na, K, Rb, Cs, and Fr. The alkali metals exist all soft, shiny, and metallic when cut. They react efficiently with water, have low melting points and densities, and are good conductors of electricity. They all include one valence electron that they lose easily to form ions. Noble gas exists as any of the seven chemical elements that create up Group 18 (VIIIa) of the periodic table. The elements exist as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).
The element of group 1 exist as reactive but those of group 18 exist as inert Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.
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Which reaction occurs at the cathode in an electrochemical cell?
A. Cu(s) → Cu2+(aq) + 2e
B. Cu2+(aq) + H2(g) → Cu(s) + 2H+(aq)
C. Cu(s) + 2H+(aq) → Cu2+(aq) + H2(g)
D. Cu2+(aq) + 2e → Cu(s)
Answer:
I could be wrong but I say it's letter b
Explanation:
I hope you have an great night
N2 H4 (1) + O2
N2 (a) + 2H20()
PLEASE HELP ASAP!
How many grams of hydrazine (N2Ha) are needed to produce 52,4 g
water?
a 31.0
O b
b. 186
c. 32.0
d. 46.5
Answer:
d. 46.5 g
Explanation:
First, you need to start with a properly balanced equation:
N₂H₄(l) + 3O₂(g) -> 2NO₂(g) + 2H₂O(l)
Then, find the moles of water produced:
2H = 2.01568 amu
O = 15.999 amu
________________
18.01468 amu
52.4 g ÷ 18.01468 amu = 2.9087 moles
The mole ratio in our balanced formula between N₂H₄ : H₂O is 1 : 2, so divide moles of H₂O by 2 to get moles of N₂H₄
2.9087 moles ÷ 2 = 1.45435 moles of N₂H₄
Then, calculate the atomic mass of N₂H₄:
2N = 28.0134 amu
4H = 4.03136 amu
________________
32.04476 amu
Finally, calculate the mass in grams of N₂H₄:
1.45435 moles • 32.04476 amu = 46.604 g
PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ PLZ HELP ME......
Answer:
a) clockwise
b) clockwise and
c) anticlockwise
2. 10.00 grams of a sample of hydrated PtCl4 are heated and lose 3.00 g of water. How many moles of water are combined with each mole of PtCl4?
Answer:
8 mol
Explanation:
Step 1: Calculate the mass of PtCl₄ in the sample
10.00 grams of a sample of hydrated PtCl₄ are heated and lose 3.00 g of water. The mass of PtCl₄ is:
mPtCl₄ = 10.00 g - 3.00 g = 7.00 g
Step 2: Calculate the moles corresponding to 7.00 g of PtCl₄ and 3.00 g of H₂O
The molar mass of PtCl₄ is 336.9 g/mol.
7.00 g × 1 mol/336.9 g = 0.0208 mol
The molar mass of H₂O is 18.02 g/mol.
3.00 g × 1 mol/18.02 g = 0.166 mol
The molar ratio of H₂O to PtCl₄ is:
0.166 mol H₂O/0.0208 mol PtCl₄ ≈ 8 mol H₂O/ 1 mol PtCl₄
Water glass is found in
A. Liquid form at room temperature
B. solid state at room temperature
c. semi liquid form at room temperature
D. None of above
Answer:
liquid form
Explanation:
am i right? if right like
Answer:
semi-liquid at room temperature
In the compound Ni2O3, nickel's oxidation number is_____
oxidation number is -2.
and oxygen's
Answer:
+3
Explanation:
The name of this compound would be nickel (III) oxide. Oxygen typically has a charge of -2. Given there are 3 oxygen atoms, that would equal a charge of -6. The nickel is the cation and must equal the charge of the anion, so must have a charge of +6. Since there are 2 nickel atoms, the charge on each must be +3.
describe the different system of measurement
Answer:
A system of measurement is a collection of units of measurement and rules relating them to each other. ... Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the British imperial system, and the United States customary system.
Explanation:
Hope it works!!!!
Answer:
Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the British imperial system, and the United States customary system.
Why does increasing the temperature make a solid dissolve faster?
- The solvent molecules bump into the solid more often.
- The solid is melted before mixing into the liquid.
- The chemical bonds of the solid are broken faster.
- The pressure of the solute on the solid is increased.
Answer:
The solvent molecules bump into the solid more often
Explanation:
Increasing the temperature makes a solid dissolve faster because the solvent molecules bump into the solid more often.
What happens when you increase the temperature of the solvent?If we heat the solvent, the average kinetic energies of its molecules increase. Hence, the solvent is able to dislodge more particles from the surface of the solute. Thus, increasing the temperature increases the solubilities of substances. For example, sugar and salt are more soluble in water at higher temperatures.
Does raising the temperature make a substance dissolve faster in a solvent?The temperature of the solvent is another factor that affects how fast a solute dissolves. Generally, a solute dissolves faster in a warmer solvent than it does in a cooler solvent because particles have more energy of movement.
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Determine the mass of oxygen in a 45.0 g sample of calcium carbonate
Answer:
The mass of oxygen in 45.0 g sample of calcium carbonate is approximately 21.58 g
Explanation:
The chemical formula for calcium carbonate is CaCO₃
The molar mass of CaCO₃ = 100.0869 g/mol
The mass of oxygen in one mole of CaCO₃ = 3 × 15.999 g = 47.997 g
The mass of oxygen in 45.0 g sample of CaCO₃, m, is goven as follows;
m = 45.0/100.0869 × 47.997 g ≈ 21.58 g
The mass of oxygen in 45.0 g sample of calcium carbonate, m ≈ 21.58 g
What species is reduced in the reaction Fe + AgNO3 → Fe(NO3)3 + Ag?
A. Agt
B. Fe
C. NO3
D. Fe3-
The species that is reduced in the reaction is Fe. Option B
The process by which an atom gains an electron, thereby lowering or decreasing its oxidation number. Basically, the positive character of the species is reduced. Reduction occurs when an atom gains one or more electrons during a chemical reaction. This means that the oxidation number decreases. This is when an atom gains an electron because electrons have a negative charge.
Acquires a negative charge that reduces the oxidation number. Reduction involves a half-reaction in which a chemical species reduces its oxidation number, usually by gaining an electron. The other half of the reaction involves oxidation in which electrons are lost. Reduction and oxidation together form a redox reaction. As the oxidation number increases, the atom is oxidized, and as the oxidation number decreases, the atom is reduced.
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Answer: Ag+
Explanation: I just took the test.
What is the meaning of salt
Answer:
a white crystalline substance that gives seawater it characteristics of taste
What is said to have happened to the electrons in an atom in its ground state absorbs a quantum of energy from light
Answer:
The electron from the ground state to occupy a next energy level. In this case,we say that the electron is excited
True or false, The universal gas constant, R, is . 0821 when we use mm Hg as our unit for pressure
Answer:
This is true.
Explanation:
R should be 0.0821
Good luck!
Please help with the Volume one
Answer:
im a just achild
Explanation:
Answer:
c
Explanation:
0.5dm³
follow me if you want
relate the pH of a solution to its hydronium and hydroxyl ion concentration and its acidity or basicity
brain list if your answer is good
when ph decrease that means acidity increase
when ph increase that means basicity increase
Molar mass calculation for Cl^2
Answer:
Mass of Cl = 35.5
Mass of Cl2 => 35.5×2
=> 71 g/mol
hope that helps ✌
71
explain:The atomic mass of chlorine is equal to the molar mass of chlorine so the molar mass of chlorine is 35.5
=> molar mass for Cl^2: 35,5*2=71
What does a pH of 7 say about a solution?
O A. The solution is at equilibrium.
B. The solution is neutral.
O C. The solution is acidic.
O D. The solution is basic.
Answer:
Its's B
The Solution is neutral
Explanation:
Name one diatomic compound which is mononuclei
Answer:
Common diatomic molecules include hydrogen (H2), nitrogen (N2), oxygen (O2), and carbon monoxide (CO). Seven elements exist as homonuclear diatomic molecules at room temperature: H2, N2, O2, F2, Cl2, Br2, and I2. The bond in a homonuclear diatomic molecule is non-polar due to the electronegativity difference of zero.
please hurry which statement is a scientist most likely to use in describing work
what is the anode material used in the extraction of aluminium by electrolysis and why it needs to be changed at interval
Answer:
the anode material is graphite(replaceable graphite rods).
The oxygen gas burns away the anode as Carbon dioxide therefore the anode must be replaced continuously.
4. what reaction fuels the burning of the sun? A.fission B.fusion C.combustion D.transmutation
Answer:
A
Explanation:
Answer:
fusion is what fuels the burning of the sun,it's the combining of light elements into heavier elements to produce energy.the sun produces a large amount of energy by combining very light elements with heavier elements.
I hope this helps
hii pls help me to balance the equation thanksss
Explanation:
2KCLO3 (s) = 2KCl (s) + 3O2 (g)
Question 10 of 10 A certain seed is surrounded by a sticky coating. It is fairly dense and does not float in water. How is this seed most likely spread?
A. It is dispersed by the wind, and it sprouts after it falls to the ground
B. It drops to the bottom of a body of water, where it sprouts.
C. It attaches to the fur of an animal, and it sprouts after it falls from the animal's fur.
D. Animals eat it, and it is deposited in their waste.
A sample of lithium sulfate, (Li2SO4), has 2.94 x 1023 atoms
of lithium. How many moles of lithium sulfate is the sample?
Answer:
0.245 moles
Explanation:
moles of lithium = 2*moles of Li2SO4
so moles of LI2SO4=2.94*10^23/(2*6*10^23)=0.245
One mole of lithium sulphate contains 1.2 .022 × 10²⁴ atoms. Thus, the number of moles of this compound which contains 2.94 × 10²³ Li atoms is 4.08 moles.
What is one mole?Any substance containing 6 .022 × 10²³ number of atoms is called one mole of that substance. This number is called Avogadro number. Hence, one mole of every elements or molecules contains Avogadro number of atoms.
Similarly, one mole of any compound contains 6 .022 × 10²³ molecules. The weight of one mole of a compound is called its molar mass. The mass of one mole of an element is called its atomic mass.
Hence, one mole of lithium sulphate contains 2 × 6 .022 × 10²³ atoms of lithium. Therefore, the number of moles of lithium sulphate containing 2.94 × 10²³ Li is :
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What is the energy of a photon that emits a light of
frequency 6.42 x 1014 Hz?
A. 4.67 x 10-19 J
B. 4.25 x 10-19
C. 3.10 x 10-19 J
D. 9.69 x 10-19 J
Answer:
Option B is correct [4.25 x 10-19J]
Explanation:
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4.78×[tex]10^{-19}[/tex] J is the energy of a photon that emits light of
frequency 6.42 x[tex]10^{14}[/tex] Hz.
What is the frequency?Frequency is the rate at which current changes direction per second. The energy of a single photon is given by:
E =hν
where
E is the energy
h is the Planck constant
f is the frequency of the light
The chemical equation for the energy of a photon is given by:
E =hν , where h is the Planck constant and ν is the frequency.
E =hν = 6.626×[tex]10^{-34}[/tex] Js × 7.21×[tex]10^ {14}[/tex]
[tex]s^{-1}[/tex] = 4.78 ×[tex]10^{-19}[/tex] J
Hence, 4.78×[tex]10^{-19}[/tex] J is the energy of a photon that emits light of
frequency 6.42 x[tex]10^{14}[/tex] Hz.
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2. A photon of wavelength for 4 x10 -7 m strikes on the metal surface the work
function of the metal being 2.13 eV.Calculate (i)the energy of the photon in
eV(ii) the kinetic energy of the emission(iii) velocity of the photoelectron
[1ev=1.602x10-19 J]
Answer:
See explanation
Explanation:
Energy of the photon;
E = hc/λ
h= Planks constant
c= speed of light
λ = wavelength
E= 6.6 × 10^-34 × 3 × 10^8/4 x10 -7
E = 4.95 × 10^-19 J
If 1ev=1.602x10-19 J
x = 4.95 × 10^-19 J
x= 3.1 ev
From Einstein's photoelectric equation;
KE = E - Wo
Where;
KE = kinetic energy of ejected photoelectron
E= energy of the photon
Wo= work function of the metal
KE = 3.1 eV - 2.13 eV
KE= 0.97 eV
KE = 0.97 eV × 1.602x10-19 J
KE = 1.55 × 10^-19 J
KE = 1/2 mv^2
1.55 × 10^-19= 1/2 × 9.1 × 10^-31 × v^2
v= √2 × 1.55 × 10^-19/9.1 × 10^-31
v= 5.8 × 10^5 m/s
