Chemicals used in hot packs do not produce fire, so what makes the hot packs feel hot?

Protons are positively charged particles that are located inside the nucleus at the center of the atom. Protons have a mass of 1 amu or atomic mass unit.

Electrons are negatively charged particles found outside the nucleus. Electrons have a mass of approximately 0 amu or atomic mass unit.

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Answer:

the valence of S is -2. For FeS to be neutral the valence of Fe used must be +2

and since Iron (II) has its valency 2, FeS will be Iron (II) Sulfide.

Answer:

174.259 g/mol

Explanation:

The molecular weight of potassium (K2so4) is 174.259 g/mol .

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Answer:

1. Absolute time, also known as Newtonian time is a time that exists independent of the observer of the time, and therefore, can only be expressed through mathematics

Absolute dating is a dating method that makes use of the radioactive property of matter and is determined through dating of radioactive isotopes present

Absolute time (dating) is found through radioactive dating

2. Radioactive isotopes are atoms that have the property of unstable proton neutron combination or excess energy nucleus. They can be fined as unstable element

3. A stabilized isotope are the decay product atoms of the element which are non radioactive.

4. The half life is the time it takes the original isotope to decay into the decay product

5. To determine the age of a rock, the proportion of the original isotope to the amount of decay product in the rock is compared

6. The isotope used to date organic materials is carbon-14

7. The isotope used to date rocks with comparable age to the Earth is Uranium-238 that has a half life of 4.468 billion years

8. The half life of carbon-14 is only 5,700 years while the age of a dinosaur is between 245 and 66 million years ago, and therefore, carbon is absent in most fossils

9. Uranium-238 is only found in igneous or volcanic rocks and not in metamorphic rocks, therefore, fossils  of dinosaur as well as other fossils that are buried in sedimentary materials, including sand and clay, cannot be determined by Uranium-238

Explanation:

Answer:

B. it's water of crystallization.

the water of crystallization, that is the number of molecules of water attached to One Copper atom gives blue color to the hydrated salt (CuSO4.5H2O)

Answer:

is your question correct

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..

.

.

.

or not

Answer:

3

Explanation:

Applying,

[tex]2^{n'}[/tex] = R/R'............... Equation 1

Where n' = number of halflives that have passed, R = Original atom of the substance, R' = atom of the substance left after decay.

From the question,

Given: R = 40 atoms, R' = 5 atoms

Substitute these values into equation 1

[tex]2^{n'}[/tex] = 40/5

[tex]2^{n'}[/tex] = 8

[tex]2^{n'}[/tex] = 2³

Equation the base,

n' = 3

Answer:

1.34 hr

Explanation:

From the question given above, the following data were obtained:

Number of mole of electron (e) = 0.1 mole

Current (I) = 2 A

Time (t) =?

Next, we shall determine the quantity of electricity transferred. This can be obtained as follow:

1 mole of electron = 96500 C

Therefore,

0.1 mole of electron = 0.1 × 96500

0.1 mole of electron = 9650 C

Thus, 9650 C of electricity was transferred.

Next, we shall determine the time. This can be obtained as follow:

Current (I) = 2 A

Quantity of electricity (Q) = 9650 C

Time (t) =?

Q = It

9650 = 2 × t

Divide both side by 2

t = 9650 / 2

t = 4825 s

Finally, we shall convert 4825 s to hour. This can be obtained as follow:

3600 s = 1 hr

Therefore,

4825 s = 4825 s× 1 hr / 3600 s

4825 s = 1.34 hr

Thus, the time taken is 1.34 hr

Answer:

Answer to the following question is as follows;

Explanation:

Alkynes' vapour pressure and normal boiling points are altered when chain length grows, since vapour pressure rises while boiling point falls.

Vapour pressure always include pressure entered by vapour with its condensed phase, pressure include molecules force of attraction include vapour

Answer:

oh it's easy

Explanation:

Take the hydrate

N

a

2

S

2

O

3

∙

5

H

2

O

. Are there ionic forces between the

N

a

+

and the

S

2

O

2

−

3

and ion-dipole forces between the cation/anions and the water?

Answer:

C. KMnO4/H+

Explanation:

Oxidizing agent is a substance that has the ability to accept electrons from other substances.

Answer:

beryllium is the answer.

I hope this will help you

Answer:

Answer is 2nd

Explanation:

some energy is transformed into mass

Answer:

No and Yes

Explanation:

it depends bc its an ionic compound, therefore can't conduct electricity when SOLID, BUT unless it DISSOLVES in water it can conduct

Answer:

1.03 grams of hydrogen is produced from 12.5 g of Mg reacting with hydrochloric acid.

Explanation:

The balanced reaction is:

Mg+ 2 HCl → MgCl₂ + H₂

By stoichiometry of the reaction, the following amounts of moles of each compound participate in the reaction:

Being the molar mass of each compound:

By reaction stoichiometry, the following mass amounts of each compound participate in the reaction:

Then you can apply the following rule of three: if by stoichiometry 24.31 grams of Mg produces 2 grams of H₂, 12.5 grams of Mg produces how much mass of H₂?

[tex]mass of H_{2} =\frac{12.5 grams of Mg* 2 grams of H_{2}}{24.31 grams of Mg}[/tex]

mass of H₂= 1.03 grams

1.03 grams of hydrogen is produced from 12.5 g of Mg reacting with hydrochloric acid.

Answer:

transition state is a point in which electrons been removed from the atom

Answer:

The highest energy structure in the reaction coordinate.

Explanation:

Answer: The labelling of each molecule is listed below:

B.) alkyne

C.) Alkane

D.) alkyne

I.) alkene

Explanation:

In organic chemistry, if an organic compound contains atoms joined only by single covalent bonds, the compound is said to be saturated. The ALKANES are said to be saturated hydrocarbons. For example butane and hexane that is shown in option F and G respectively. If an organic compound contains carbon atoms joined by double or triple covalent bonds, the compound is said to be unsaturated. For example Octene and butyne as seen in option E and H respectively.

Furthermore, hydrocarbons possess8g a set of carbon-carbon double covalent bonds,>C=C<, in their carbon chains form the homologous series called ALKENES while those possessing a set of carbon-carbon triple covalent bond in their carbon chains form the ALKYNE series

From the questions above, a more informative formula known as the structural formula is used to represent the various organic substances. The formula indicates how the atoms are arranged within the molecule of a substance. A structural formula is usually shown as a planar for convenience and does not imply a flat molecule. It shows the actual arrangement of the atoms in space and the angles between the bonds. Therefore options C, D and I are alkane,alkyne and alkene respectively.

The covalent bond with the greatest polarity would form in this atom pair: B. S-O.

Ionic character refers to a percentage of difference between the electronegativity (polarity) of two (2) atoms that are bonded covalently.

Hence, ionic character is directly proportional to the difference between the electronegativity (polarity) of two (2) atoms that forms a covalent bond.

Furthermore, bonded atoms of chemical element that are having the greatest difference in electronegativity usually forms covalent bonds with the greatest polarity.

The electronegativity of some of the chemical element are:

By observation, the difference between the electronegativity (polarity) of Sulfur (S) and Oxygen (0) would form a covalent bond with the greatest polarity.

                       [tex]S-O=3.5-2.58=0.92[/tex]

Read more: https://brainly.com/question/18214726

Answer:

87059.50558 pa

Explanation:

Dalton's law of partial pressure states that Ptotal=P1 +P2+ P3

417mmHg + 150mmHg +86mmHg =653 mmHg

convert it to Pa, your answer is 87059.50558Pa.

I hope I'm of help to you

Answer:

may be you mean water= hydrogen + oxygen, this reaction describes that water is made by the combination of hydrogen and oxygen.

Answer:

The correct answer is - butanoic acid

Explanation:

An empirical formula is the general formula or base formula that is the simplest positive integer ratio of atoms present in a compound. The empirical formula is specific to specific compounds or types of compounds.

Among the given options, the empirical formula C2H4O is butanoic acid as the molecular formula of butanoic acid is - C4H8O2 which is multiple of C2H4O. Other compounds have different than this empirical formula.

The question is incomplete, the complete question is;

.On heating 12.4 g of copper (II) carbonate in a crucible only 7.0g of copper (II) oxide was produced. What was the % yield of copper (II) oxide ? [Cu=64,C=12,O=16]

Answer:

87.5%

Explanation:

CuCO3 -------> CuO + CO2

Number of moles of CuCO3 = 12.4g/123.55 g/mol = 0.1 moles

Since the reaction is 1:1,

Mass of CuO produced = 0.1 moles × 80g/mol = 8 g

Hence,

% yield = actual yield/theoretical yield × 100

% yield = 7/8 × 100

% yield = 87.5%

Answer:

c hierro

no se la otra sorry

Question 24:

Answer C : Q is placed in group 13 and period 2.

Question 25:

Answer C : II and IV.

Question 26:

Answer D