Which of these elements is the most reactive?potassium
calcium
titanium
scandium

Answers

Answer 1

Answer:

Answer:

Scandium

Explanation:

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In which substance do the molecules have the strongest attractions to one another ?
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Which compound would most likely turn litmus paper to a red color?a. CH₃CH₂CH₂OH b. CH₃CH(Br)CH(Br)CH₃ c. CH₃CH₂CH(Br)CH₃ d. CH₃CH₂CH₂COOH e. CH₃CH₂CH₂CH₃
A chemist places a flask containing the reactants in an ice bath. This will _____ the rate of the reaction. increase decrease

The reaction below demonstrates which characteristic of a base?CuSO4(aq)+2NaOH(aq)->Cu(OH)2(s)+Na2SO4
the ability of bases to release sodium ions into solution
the ability of bases to release hydrogen ions into solution
the ability of a base to react with carbonate or bicarbonate
the ability of a base to react with a soluble metal salt

Answers

I think the correct answer from the choices listed above is the last option. The reaction below demonstrates a characteristic of base which is the ability of a base to react with a soluble metal salt. Hope this answers the question. Have a nice day.

In the reaction of the type:
CuSO4(aq) + 2NaOH(aq) -> Cu(OH)2(s) + Na2SO4

Herein, base (NaOH) reacts with water soluble metal salt (CuSO4) to form metal hydroxide.

This displays ability of a base to react with a soluble metal salt. Hence correct answer is option D.

For the following reaction: Fe2O3 + 3CO --> 2Fe + 3CO2 how many grams of Fe2O3 is needed to produce 111 g of Fe?

Answers

You need 158.70 grams of Fe2O3 to produce 111 grams of Fe. This is calculated by using the molar masses and stoichiometric relationship of the two compounds.

Solution:

MM Fe = 55.845 g/mol
MM Fe2O3 = 159.69 g/mol
Fe: Fe2O3 = 2 mol:1 mol

11 g FE (1 mol Fe/55.845 g Fe) (1 mol Fe2O3/2 mol Fe) (159.69 g Fe2O3 / 1 mole Fe2O3) = 158.70 grams Fe2O3

Which of these features was formed by hotspot volcanism?The Grand Canyon
The Big Island of Hawaii
The Appalachian Mountains
The Himalaya Mountain Range

Answers

These feature that was formed by hotspot volcanism is The Big Island of Hawaii. The Hawaiian Islands are actually found at the tip of several volcanoes that has been formed by a series of volcanic eruptions. Today, the Big Island sits on the hotspot, and contains the only active volcanoes of the group of islands.

The Big Island of Hawaii was formed by hotspot volcanism, whereas The Grand Canyon, The Appalachian Mountains, and The Himalaya Mountain Range were not.

Use the born-haber cycle to calculate the lattice energy of kcl. (δhsub for potassium is 89.0 kj/mol, ie1 for potassium is 419 kj/mol, ea1 for chlorine is −349 kj/mol, the bond energy of cl2 is 243 kj/mol, δh∘f for kcl is −436.5 kj/mol .)

Answers

Given data:

Sublimation of K

K(s) ↔ K(g) ΔH(sub) = 89.0 kj/mol

Ionization energy for K

K(s) → K⁺ + e⁻ IE(K) = 419 Kj/mol

Electron affinity for Cl

Cl(g) + e⁻ → Cl⁻ EA(Cl) = -349 kj/mol

Bond energy for Cl₂

1/2Cl₂ (g) → Cl Bond energy = 243/2 = 121.5 kj/mol

Formation of KCl

K(s) + 1/2Cl₂(g) → KCl(s) ΔHf = -436.5 kJ/mol

To determine:

Lattice energy of KCl

K⁺(g) + Cl⁻(g) → KCl (s) U(KCl) = ?

Explanation:

The enthalpy of formation of KCl can be expressed in terms of the sum of all the above processes, i.e.

ΔHf(KCl) = U(KCl) + ΔH(sub) + IE(K) + 1/2 BE(Cl₂) + EA(Cl)

therefore:

U(KCl) = ΔHf(KCl) - [ΔH(sub) + IE(K) + 1/2 BE(Cl₂) + EA(Cl)]

= -436.5 - [89 + 419 + 243/2 -349] = -717 kJ/mol

Ans: the lattice energy of KCl = -717 kj/mol

Final answer:

The lattice energy of KCl is calculated using the Born-Haber cycle by considering the energies of several steps including the sublimation of potassium, ionization of potassium, dissociation of Cl bond, electron affinity of Cl, and formation of KCl. The given values are plugged into a formula resulting in a lattice energy of -718 kJ/mol.

Explanation:

To calculate the lattice energy of KCl using the Born-Haber cycle, we need to follow several thermochemical steps. The steps include, first sublimation of potassium, the ionization of potassium, bond dissociation enthalpy to produce Cl, the electron affinity of Cl, and formation of KCl (s). Combining energy changes associated with all these steps would give us energy change for the formation of KCl from individual K and Cl2, it is called as enthalpy of formation (ΔH°f) for KCl.

Using the given values for each step, we use the formula: ΔH°f = ΔHsub + IE1 + 1/2* DCl2 - EA1 + lattice energy.

Substituting the given values, -436.5 = 89 + 419 + 1/2*243 -349 + lattice energy. Solving gives the lattice energy as -718 kJ/mol.

Learn more about Lattice energy calculation here:

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When dissolved in water, all acids willA. Form hydroxide ions B. have a negative eletrical charger C. conduct eletricity D. turn blue

Answers

When dissolved in water, all acids will conduct electricity. The correct answer is C.

4. If an object has a density of 0.8 g/cm3, will it float or sink in water?

Answers

Explanation:

Substances with their density less than the density of water which is 1 g/cm³ will float on it whiles those greater than that of water will sink into the water.

From the question the density of the object is 0.8 g/cm³

Since it's density is less than that of water the object will float on water .

Hope this helps you

Final answer:

An object with a density of 0.8 g/cm3 will float in water because its density is less than the density of water, which is 1 g/cm3.

Explanation:

The question is asking whether an object with a density of 0.8 g/cm3 will float or sink in water. Floating and sinking are determined by the principle of buoyancy, which depends on the density of the object compared to the fluid (in this case, water) it is placed in.

Water has a density of 1 g/cm3. So, if the object's density is less than 1 g/cm3, it will float, if it's more it will sink. Since 0.8 g/cm3 is less than 1 g/cm3, an object with this density will float in water.