A student electrolysed some water. She collected 20 cm of oxygen, What volume of hydrogen could she also
have collected at the same time?

Answer:humans have put ridiculous amounts of carbon dioxide into the atmosphereThese events are linked to the mass burning of fossil fuels to meet an increase in human demand

So the answer is True

Explanation:

Burning fossil fuels, such as coal and oil, has increased the quantity of greenhouse gases in our atmosphere since the Industrial Revolution began around 1750.

Atmosphere is defined as a layer of gas that surrounds a planet and is kept there by the gravitational pull of the planetary body. The atmosphere of Earth includes five primary layers and a number of minor ones.

Industrial revolution is defined as the transition of an economy based on agriculture and handicrafts to one driven by industry and machine production. The causes of industrial revolution are the advent of capitalism, European imperialism, efforts to mine coal, and the effects of the Agricultural Revolution are some of the factors that historians have recognized as contributing to the Industrial Revolution.

Thus, burning fossil fuels, such as coal and oil, has increased the quantity of greenhouse gases in our atmosphere since the Industrial Revolution began around 1750.

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Answer:

D

Explanation:

BEcause you are testing which objects will stick. Your control variable will be the sweater. And the number of times you rub the object on the sweter will not make it stick. It will make it stick for a longer period.

Answer:

D. The type of objects you are testing in the experiment

Answer:

The original marshmallow was named for the inclusion of marshmallow root in the recipe. The roots and leaves of the marshmallow plant contain mucilage, a slimy-textured demulcent best known for its use as a homeopathic cough suppressant. Marshmallow root is considered to be soothing and mildly antimicrobial. It has long been used as an herbal treatment for minor digestive issues and skin irritations, although its use in the creation of its namesake confection has long since fallen by the wayside.

Explanation:

So basically salt makes it strecthy! Please mark brainliest!!

Catalysts speed up chemical reactions / changes.

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Noble gases are the least reactive of all elements. That's because they have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.

Group 18; The Noble Gases contains the elements on the periodic table that would be the least reactive out of all the elements. So, this include any gas element, such as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og). Hence, if you have the options:

(The Option in Bold is Correct)

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Hope this helps!

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Explanation:

M = molar mass

p= percentage abundance

[tex]rel.atm.mass = \frac{ M1p1 + M2p2 + M3p3}{100} \\ r.a.m = \frac{24 \times 78.99 + 25 \times 10 + 26 \times 11.01}{100} \\ r.a.m = \frac{1895.76 + 250 + 286.26}{100} \\ = \frac{2432.02}{100} \\ 24.32[/tex]

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Answer:

hydrogen bonds

Explanation:

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The unusual chemical properties of water is due to its polar covalent bond.

When atoms with differing electronegativities are shared between two atoms in such a covalent link, the result would be a polar covalent bond.

Water is a kind of mixture of hydrogen and oxygen . Its chemical formula will be [tex]H_{2}O[/tex].

Along with its polar covalent connections, water displays a variety of interesting features. Because oxygen has a higher electronegativity than hydrogen, electron pairs were drawn closer to the oxygen atom, causing it to be partially negatively charged. As a result, both hydrogen atoms acquire a slightly positive charge.

Therefore, polar covalent bond will be responsible for unusual chemical properties of water.

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The energy of a single photon of this frequency is 1.638 × 10⁻¹⁸ J

Using Planck's equation, the energy of the photon E = hf where h = Planck's constant = 6.63 × 10⁻³⁴ Js and f = frequency of ultraviolet light = 2.47 × 10⁻¹⁵ Hz.

Substituting the values of the variables into the equation, we have

E = hf

E = 6.63 × 10⁻³⁴ Js × 2.47 × 10¹⁵ Hz.

E = 16.3761 × 10⁻¹⁹ J

E = 1.63761 × 10⁻¹⁸ J

E ≅ 1.638 × 10⁻¹⁸ J

So, the energy of a single photon of this frequency is 1.638 × 10⁻¹⁸ J

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Answer:

Decane doesn't have any free electrons because all the electrons of carbon is used for bonding.

Considering the definition of STP conditions, 28 grams of O₂ will ocupy at STP 19.6 L.

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

On the other side, the molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

In this case, you  have 28 g of O₂. The molar mass es 32 [tex]\frac{g}{mole}[/tex]

Next, you can apply the following rule of three: if 32 grams of the compound are contained in 1 mole, 28 grams are contained in how many moles?

[tex]number of moles=\frac{28 gramsx1 mole}{32 grams}[/tex]

number of moles= 0.875 moles

Now, you can apply the following rule of three: if by definition of STP conditions 1 mole of O₂ occupies a volume of 22.4 liters, 0.875 moles occupies how much volume?

[tex]volume=\frac{0.875 molesx22.4 L}{1 mole}[/tex]

volume= 19.6 L

Finally, 28 grams of O₂ will ocupy at STP 19.6 L.

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i dont know im only doing for points

Answer: They begin to overlap

The phrase which best describes the vapor point of a substance is Choice C; the temperature at which additional heat energy causes the substance to change from a liquid to a gas.

The vapour point of a substance by definition is the state of a substance at which upon addition of any amount of heat energy; he substance undergoes a phase change from liquid to solid.

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Answer:

Aluminum generally forms Al3+ ions. Oxygen generally forms O2− ions. So when the metal and the non-metal make music together they form a neutral compound, i.e. Al2O3 (i.e. 2×3−3×2=0) . The ionic bonding is so strong (due to charge magnitude) in this material that it is reasonably insoluble.

Explanation:

Explanation:

this is because the combining capacity, ie valency, of Pb is 2 of which NO3 is 1. So, when they will combine by cross method, the compound become Pb(NO3)2 (lead II nitrate).

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Answer:

metal in group 5A is bismuth

electronic configuration : 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 4d^10 5s^2 5p^6 4f^14 5d^10 6s^2 6p3

alkali metal in period 2 is lithium

1s^2 2s^ 1

Explanation:

Answer:

its letter d ..................................

Answer:

92.4%

Explanation:

Assume 100g of the cathode material. The LiCoO2 cathode has 7.09 g of Li.  If half of Li migrates during charging, 3.55g Li migrates. 100g of the LiMn2O4 cathode contain 3.84g of Li. The fraction of lithium in LiMn2O4 that would need to migrate out of the cathode to deliver the same amount of lithium to the graphite anode:

(3.55g/ 3.84g ) * 100% = 92.4%

From electrolysis, 92.4% would need to migrate out of the cathode to deliver the same amount of lithium to the graphite anode.

Electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. The voltage that is needed for electrolysis to occur is called the decomposition potential.

Assume 100 g of the cathode material. The LiCoO₂ cathode has 7.09 g of Li.  If half of Li migrates during charging, 3.55 g Li migrates. 100 g of the LiMn₂O₄cathode contain 3.84 g of Li. The fraction of lithium in LiMn₂O₄ that would need to migrate out of the cathode to deliver the same amount of lithium to the graphite anode:(3.55 g/ 3.84 g ) × 100% = 92.4%

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Answer:

nucleus

Explanation:

The nucleus contains the majority of an atom's mass because protons and neutrons are much heavier than electrons, whereas electrons occupy almost all of an atom's volume

Answer:

0.625

Explanation:

If you are referring the O2, first you need to get the relative mass of it. You can see the O's is around 16. but this is O2,you need to multiple it.

16×2=32

We get the equation n=m/M where m is for gram

20/32=0.625mol

Answer:

D All of the above

[tex] \: [/tex]

Answer:

25%

Explanation:

Percent by mass is looking at the percentage of mass within a a solution. So since there's 100g of water and 25 grams of sugar, you divide 25 by 100 to get the ratio. Then multiply by 100 to get the percentage.

Answer:

To calculate the number of neutrons, subtract the atomic number (which equals the number of protons) from the mass number.

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Answer:

GRAPHENE is a single layer of graphite

Explanation:

each carbon atom bonded to 3 other carbon atoms forming a hexagonal lattice