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2 years ago

Help me please i need this aaaaaaaaa <3

Chemistry

2 answers:

Shtirlitz [24]2 years ago

6 0

Answer:

1.magma forms beneath the plates and rises up through the cracks

2. the tectonic plates move apart from one another

3. lava flows onto Earth’s surface

4. lava cools and hardens to form igneous rock

Explanation:

mylen [45]2 years ago

4 0

Can someone help me out too? , on my question?

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Assuming equal concentrations and complete dissociation, rank these aqueous solutions by their freezing points. K2SO4 NH4I CoCl3

katrin [286]

The substance that releases the greatest amount of ions will have the greatest attractive forces within its solution, resulting in a reduced freezing point.
K₂SO₄ yields 3 ions
NH₄I yields 2 ions
CoCl₃ yields 4 ions

Freezing points:
CoCl₃ < K₂SO₄ < NH₄I

8 0

3 years ago

In the process of attempting to characterize a substance, a chemist makes the following observations: (a) The substance is a sil

Amiraneli [1.4K]

The question is incomplete, this is the complete question;

In the process of attempting to characterize a substance, a chemist makes the following observations. Which are physical properties and which are chemical properties?

(a) The substance is a silvery white, lustrous metal.

(b) The substance melts at 649 ∘C

(d) The density of the substance at 20 ∘C is 1.738 g/cm³.

(e) The substance burns in air, producing an intense white light.

(f) The substance reacts with chlorine to give a brittle white solid.

(g) The substance can be pounded into thin sheets or drawn into wires.

(h) The substance is a good conductor of electricity.

Answer:

(a) Physical

(b) Physical

(d) Physical

(e) Chemical

(f) Chemical

(g) Physical

(h) Physical

Explanation:

(a) The substance is a silvery white, lustrous metal - is appearance which is physical.

(b) The substance melts at 649 ∘C metling point is a physical measurement

(d) The density of the substance at 20 ∘C is 1.738 g/cm3 how heavy a substance is,is physical.

(e) The substance burns in air, producing an intense white light. Burning is a chemical change. It is a reaction of a substance with oxygen

(f) The substance reacts with chlorine to give a brittle white solid. This is a chemical reaction as the question says.

(g) The substance can be pounded into thin sheets or drawn into wires. Ductility is a physical change, the substance remains chemically unchanged

(h) The substance is a good conductor of electricity. Any conductivity is physical, the substance remains chemically unchanged

7 0

3 years ago

What bonds of the reactants are broken in this reaction? What bonds are formed in the product?

Y_Kistochka [10]

<span>Bonds of reactants are broken and create new bonds to form different products and produces exothermic and endothermic reactions.
You are able to see a chemical reaction occur through a few signs
hope this helps

</span>

7 0

3 years ago

Calculate the cell potential at 25oC under the following nonstandard conditions: 2MnO4-(aq) + 3Cu(s) + 8H+(aq) ⟶ 2MnO2(s) + 3Cu2

baherus [9]

Answer:

1.346 v

Explanation:

1) Fist of all we need to calculate the standard cell potential, one should look up the reduction potentials for the species envolved:

(oxidation) $Cu_{(s)}$ → $Cu^{2+}_{(aq)} +2e$ E°=0.337 v

(reduction) $MnO_{4 (aq)} + 3e + 4H^{+}_{(aq)}$ → $MnO_{2 (aq)}+2H_{2}O$ E°=1.679 v

(overall) $2MnO_{4 (aq)}+3Cu_{(s)}$ +8H^{+}_{(aq)}→ $3Cu^{2+}_{(aq)}+2MnO_{2 (aq)}+4H_{2}O$ E°=1.342 v

2) Nernst Equation

Knowing the standard potential, one calculates the nonstandard potential using the Nernst Equation:

$E=E^{0} -\frac{RT}{nF}Ln\frac{[red]}{[ox]}$

Where 'R' is the molar gas constant, 'T' is the kelvin temperature, 'n' is the number of electrons involved in the reaction and 'F' is the faraday constant.

The problem gives the [red]=0.66M and [ox]=1.69M, just apply to the Nernst Equation to give

$E=1.342 -\frac{298.15*8.314}{6*96500}Ln\frac{[.66]}{[1.69]}=1.346$

E=1.346

5 0

2 years ago

Why does the temperature of the water stay the same when it melts and boils?

krok68 [10]

The temperature stays the same when a solid changes to a liquid because energy is required to break the forces between particles of water therefore changing the state of matter and separating the particles away from each other.

When a liquid boils, the energy is needed by the particles to escape the surface of the liquid and boil. Instead of raising the temperature, the energy goes into the particles' kinetic energy store so it has enough speed to escape the surface of the liquid.

5 0

3 years ago