Hard water contains calcium and magnesium, which undergo oxidation andclog water pipes. Which statement best describes this change as a chemical change?

A.Calcium and magnesium dissolve in water.

B.Calcium and magnesium evaporate on contact with the walls of the pipe.

C.Calcium and magnesium form precipitates of their respective oxides.

Answer:

the change in internal energy per mole of sucrose is 5989 KJ/mol

Explanation:

Since the calorimeter is a bomb calorimeter , where the volume remains constant

ΔE= Qrx

And assuming no heat losses to the surroundings

Qv + Qrx = 0

Cc*ΔT - Qrx = 0 ,

Qrx = Cc * ΔT = 7.50 KJ/°C * 22 °C = 165 KJ

the change in internal energy is calculated dividing by the number of sucrose moles involved n. the molecular weight of sucrose is

Mw= 12* 12g/mol + 22* 1g/mol + 11* 16 g/mol = 342 g/mol

n = m / Mw = 10 g / 342 g/mol = 0.029 mol

the change in internal energy per mole of sucrose is

Δe= ΔE/n = 165 KJ/0.029 mol = 5989 KJ/mol

Answer:

Cobalt is indeed a metal, and its atoms exhibit certain characteristics and interactions with other cobalt atoms. Here are some key features:

Atomic Structure: The cobalt atom has an atomic number of 27, meaning it has 27 protons in its nucleus. It also typically contains 27 electrons, arranged in energy levels or shells around the nucleus. The electron configuration of cobalt is [Ar] 3d^7 4s^2.

Magnetic Properties: Cobalt is known for its magnetic properties. At room temperature, it is ferromagnetic, meaning it can be permanently magnetized. This is due to the arrangement of electrons in its outermost energy levels.

Metallic Bonding: In solid cobalt, metallic bonding occurs. Metallic bonding involves the sharing of electrons between atoms within a metal lattice. In cobalt, the outermost electrons are relatively free to move throughout the metal structure, forming a "sea" of delocalized electrons. This contributes to the metal's electrical and thermal conductivity.

Alloy Formation: Cobalt readily forms alloys with other metals. Common examples include cobalt-chromium (Co-Cr) and cobalt-nickel (Co-Ni) alloys. These alloys often exhibit enhanced strength, hardness, and resistance to corrosion.

Coordination Chemistry: Cobalt is known to form coordination complexes due to its ability to act as a Lewis acid. It can form bonds with ligands, which are typically molecules or ions with lone pairs of electrons. These complexes play a crucial role in various chemical reactions, including catalysis.

Oxidation States: Cobalt can exist in different oxidation states, including +2, +3, and +4. The +2 oxidation state is the most common for cobalt and is stable in many compounds. Cobalt compounds with different oxidation states exhibit diverse chemical and physical properties.

Overall, cobalt atoms in metallic cobalt interact through metallic bonding, while cobalt in compounds can participate in coordination chemistry and exhibit different oxidation states, leading to a wide range of applications and reactivity.

Explanation:

The total number of moles of atoms in Pb(C₂H₃O₂)₂ is 66.242 x 10²³ atoms.

What is mole?

The total number of moles of atoms, use Avogadro's number, which is approximately 6.022 x 10²³ particles (atoms or molecules) per mole.

The molecular formula of Pb(C₂H₃O₂)₂ has one lead (Pb) atom, two carbon (C) atoms, four hydrogen (H) atoms, and four oxygen (O) atoms in one molecule of the compound.

So, the total number of moles of atoms in one mole of Pb(C₂H₃O₂)₂ can be calculated as follows:

1 Pb atom x (1 mole Pb / 1 mole Pb(C₂H₃O₂)₂ x (6.022 x 10²³ atoms / 1 mole Pb) = 6.022 x 10²³ Pb atoms

2 C atoms x (1 mole C / 1 molePb(C₂H₃O₂)₂ x (6.022 x 10²³ atoms / 1 mole C) = 12.044 x 10²³ C atoms

4 H atoms x (1 mole H / 1 mole Pb(C₂H₃O₂)₂ x (6.022 x 10²³ atoms / 1 mole H) = 24.088 x 10²³ H atoms

4 O atoms x (1 mole O / 1 mole Pb(C₂H₃O₂)₂ x (6.022 x 10²³ atoms / 1 mole O) = 24.088 x 1023 O atoms.

6.022 x 10²³ Pb atoms + 12.044 x 10² C atoms + 24.088 x 10²³ H atoms + 24.088 x 10²³ O atoms = 66.242 x 10²³ atoms

Therefore, there are approximately 66.242 x 10²³ atoms in one mole of Pb(C₂H₃O₂)₂.

To learn more about the mole, follow the link:

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The addition of a proton to the sulfur atom has resulted in the formation of an isotope. Thus, option A is correct.

The addition of a proton to the nucleus has been resulted in the change in the atomic mass of the element without changing the atomic number.

The atomic mass has been the number of protons and neutrons present in the nucleus. The ions have been resulted when there has been a change in the number of electrons in the atom.

The isotopes have been the element that has been considered of the same atomic number with different atomic masses.  The addition of a proton to the sulfur atom changes its atomic mass and thereby forms the isotope of sulfur. Thus, option A is correct.

For more information about the protons and electrons, refer to the link:

brainly.com/question/803445

Answer:

Created a positively charged ion of Sulfur

Explanation:

As the number of protons in Sulfur is more than the electrons in Sulfur, thus it'll be a positively charged ion of Sulfur