should i tell my parents i got C+ in chemistry or not ?

The enthalpy of reaction for the decomposition of calcium carbonate is 177.4  KJ/mole .

We know that the enthalpy of reaction can be obtained from the enthalpy of formation of the reactants and that of the products using the formula;

ΔHrxn = ΔHf (products) - ΔHf (reactants)

The heat of formation of the species are as follows;

ΔHf (CaCO3(s)) = −1206.9 KJ/mol

ΔHf (CaO(s)) =  - 636 KJ/mole

ΔHf (CO2(g)) = -393.5  KJ/mole

ΔHrxn = [( -393.5  KJ/mole ) + ( - 636 KJ/mole)] - [ −1206.9 KJ/mol]

ΔHrxn = 177.4  KJ/mole

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Answer:

First one is 656.3 and second is endothermic.

Explanation:

Edge Thermochemical Equations assignment

Answer:

B.chlorine ,Cl2 is the one

HEY!

Mayonnaise is an oil in water (O/W) emulsion; ingre- dients are primarily vegetable oil, egg yolk, sodium chloride, water and vinegar. Its relative stability towards microbial spoil- age has been attributed to the high salt content (in the water phase) and low pH, due to the vinegar.

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Taking into account the Brønsted-Lowry acid-base theory, a base/conjugate acid pair is H₂O/H₃O⁺.

The Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.

According to this theory, acids are proton donors while bases are proton acceptors. That is, an acid is a species that donates an H⁺ proton while a base is a chemical species that accepts an H⁺ proton from the acid.

So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.

In other words, a conjugate base is an ion or molecule resulting from the acid that loses the proton, while a conjugate acid is an ion or molecule resulting from the base that gains the proton:

acid + base ⇄ conjugate base + conjugate acid

In this case, you know:

H₂PO₄ + H₂O → H₃O⁺ + HPO₄⁻

H₂PO₄ behaves like acid because donates an H⁺ proton while H₂O behaves like base because accepts an H⁺ proton from the acid.

So, H₃O⁺ is the conjugate acid of the H₂O and HPO₄⁻ is conjugate base of H₂PO₄.

In summary,  a base/conjugate acid pair is H₂O/H₃O⁺.

Learn more about the Brønsted-Lowry acid-base theory:

When the egg first forms it's only one cell, and is fertilized as it moves down the oviduct to be laid

__________________________________________________________

this point it's technically an embryo : though it doesn't look like a baby chick

___________________________________________________________

o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0o0

Using the Rydberg formula, the spectral line of H - atom is suitable for this purpose is Paschen, ∞ → 3.

1/λ = RH(1/nf^2 - 1/ni^2)

Given that;

λ = wavelength

RH = Rydberg constant

nf = final state

ni = initial state

Then;

1/λ =  1 × 10^7 m-1 (1/3^2 - 1/ ∞^2)

1/λ =  1 × 10^7 m-1 (1/3^2 )

λ = 900 nm

Hence, the correct answer is Paschen, ∞ → 3

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Answer:

Carbon Dioxide is a non-flammable gas that extinguishes fire by displacing oxygen

CO2s are designed for Class B and C (flammable liquid and electrical) fires only.

Answer:

Thermal energy typically flows from a warmer material to a cooler material.

Explanation:

Substance A is less soluble in water than Substance B.

In this experiment, we can see that small amount of substance A is present at the bottom of the beaker which means that some amount of substance A does not dissolve in water.

While on the other hand, no substance B is present at the bottom of beaker which shows that all the substance B is dissolved in water so we can made a conclusion that Substance A is less soluble in water than Substance B.

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The answer would be B.

When glucose reacts with oxygen, it forms an ATP that is used by the given cell. Co2 and h2O are the byproducts.

Answer:

The pressure of 16.25 moles of methane = 40 atm

Explanation: there you go

Answer:

Sodium has 11 protons and Magnesium has 12. The way that the periodic table is set up doesn't allow for any elements to be in between. The element would have to have 11.5 protons, which is impossible

Structure of periodic table is designed in a way that successive elements have difference of 1 electron and proton as sodium and magnesium have 11 and 12 protons respectively there is no space for any other element.

Periodic table is a tabular arrangement of elements in the form of a table. In the periodic table, elements are arranged according to the modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.

It is called as periodic because properties repeat after regular intervals of atomic numbers . It is a tabular arrangement consisting of seven horizontal rows called periods and eighteen vertical columns called groups.

Elements present in the same group have same number of valence electrons and hence have similar properties while elements present in the same period show gradual variation in properties due to addition of one electron for each successive element in a period.

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Answer:

10.09 grams

Explanation:

First you need to know the number of moles you are dealing with.

If you know that each mole has 6.022x10²³ of something (in this case of atoms), you can divide 3x10²³ atoms of neons by 6.022x10²³ to obtain the number of moles.

You have 0.5 moles of Neon, so then by the periodic table, you see that the molar mass of neon is 20.18g/mol, so by each mole you have 20.18 grams of neon. Multiply 20.18 grams by 0.5 moles and you got 10.09 grams of Neon

Answer:

D Robert Boyle

Explanation:

Answer:

This is because, within a period or family of elements, all electrons are added to the same shell.

When we move from left to right across the periodic table, we can see that the atomic radii keeps decreasing. This is because, as you move from left to right, the nucleus gains protons. The atomic number increases and hence the valence electron will feel more attracted towards the nucleus & the atomic radii will decrease.

[tex]\mathbb{MIREU}[/tex]

Answer:

Explanation:

how do u draw on here

Finding molar mass of NaOH

We know that

Molar mass of Sodium (Na) = 23 g/mol

Molar mass of Oxygen (O) = 32 g/mol

Molar mass of Hydrogen (H) = 2 g/mol

So,

Mass of 1 mole of NaOH

=> 1 × 23 + 1 × 16 + 1 × 1

=> 23 + 16 + 1

=> 40 g/mol

Now,

Mass = 40 × 0.25

Mass = 10 g

Answer:

Chemistry is the branch of science that deals with the properties, composition, and structure of elements and compounds, how they can change, and the energy that is released or absorbed when they change.

Answer:

Well my  teacher said a more complex way he said chemistry is the science that deals with the properties, composition, and structure of substances.

Explanation:

Answer:

try elcetrons

Explanation:

if not then i'm sorry

The light blue area represents electrons.

An electron is a negatively charged subatomic particle. It can be either free (not attached to any atom) or bound to the nucleus of an atom. Electrons in atoms exist in spherical shells of various radii, representing energy levels. The larger the spherical shell, the higher the energy contained in the electron.

Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions.

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Answer:

True

Explanation:

the empirical formula usually shows us the atoms' symbols and then how much of them are present in this certain compound. For example there is H2O

Answer:

D is correct

Explanation:

Answer:

A

Explanation:

Electrons are gained by the atoms. There is no change in the nucleus of the atom and the number of protons remains identical.

Answer:

Dived the numbers by each other

Explanation:

25.3/19.9

Answer:

17.19%

Explanation:

mass of oxygen = 7.221 - (1.990 + 2.341)

= 2.890g

Empirical formula of the compound

For carbon,

1.990/12 = 0.1658

For hydrogen,

2.341/1 = 2.341

For oxygen,

2.890/16 = 0.1806

0.1658 ÷ 0.1658 = 1

2.341 ÷ 0.1658 = 14.11

0.1806 ÷ 0.1658 = 1.089

Empirical formula of the compound= CH14O

Molar mass= (1×12) + (14×1) + (1×16)

= 12+14+16

= 42g/mol

percentage composition= 7.221/42 × 100

= 17.19%

Answer:

Change in colour is a chemical change.

Explanation:

Because when two substances combine chemically, they create (a) new substance(s) that have/has different molecular structures from the parent substances, thus mostly likely absorb and reflect light in different ways.

Answer:

The atomic mass

Explanation:

Answer: atomic mass

Answer:

he introduced triads of similar chemical properties in periodic table.

Explanation: