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LenaWriter [7]
2 years ago
10

5) answer is A

Chemistry
1 answer:
Burka [1]2 years ago
3 0

Answer:

A)  positive; added

Explanation:

Based on the reaction:

2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)

<em>2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.</em>

<em />

That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.

Thus, right answer is:

A)  positive; added

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Which action would shift this reaction away from solid calcium fluoride and toward the dissolved ions? which action would shift
ANTONII [103]
Hello!

The chemical reaction for the dissolving of calcium fluoride is the following:

CaF₂(s) ⇄ Ca⁺²(aq) + 2F⁻(aq)

In this reaction, and according to Le Chatelier's principle, the action that would shift this reaction away from solid calcium fluoride and towards the dissolved ions is the removing of fluoride ions.

Le Chatelier's principle
states that in an equilibrium reaction, the system would shift in the opposite direction of the changes. If we remove fluoride ions from the system, it will shift towards the formation of more fluoride ions by dissolving more Calcium Fluoride to achieve equilibrium again.

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3 years ago
Warm air and water both tend to rise while cooler air and water sink. When different parts of the oceans are heated unevenly, th
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Answer:

a

Explanation:

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3 years ago
Define internuclear distance.
kotykmax [81]
Internuclear distance can be defined as the distance between the nuclei atoms, i.e.,the distance between the center of nucleus to the outer most shell of an atom.
6 0
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It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry
Fittoniya [83]

Answer:

a) Pf = 689.4 bar

b) P = 226.6 bar

c) T = 269.99 K

Explanation:

a)

The molar volume of ice is equal to:

Vi = m/p = (18.02x10^-3 kg H2O/1 mol H2O)*(1 m^3/920 kg) = 1.96x10^-5 m^3 mol^-1

The molar volume of liquid water is equal to:

Vl = (18.02x10^-3 kg/1 mol)*(1 m^3/997 kg) = 1.8x10^-5 m^3 mol^-1

The change in volume is equal to:

ΔVchange = Vi-Vl = 1.96x10^-5 - 1.8x10^-5 = 1.5x10^-6 m^3 mol^-1

using the Clapeyron equation:

Pf = Pi + ((ΔHf*ΔT)/(ΔVf*Ti)) = 1.013x10^5 Pa + ((6010 J mol^-1 * 4.7 K)/(1.5x10^-6 * 273.15 K)) = 6.89x10^7 Pa = 689.4 bar

b)

For the pressure we will use the equation:

P = (m*g)/A, where m is the mass, g is the acceleration of gravity and A is the area. Replacing values:

P = (79 kg * 9.81 m s^-2)/(1.9x10^-4 m * 0.18 m) = 2.26x10^7 Pa = 226.6 bar

c)

From Clapeyron´s expression we need to clear ΔT:

ΔT = ((Pf-Pi)*ΔV*Ti)/ΔHf = ((2.26x10^7 - 6.89x10^7)*1.5x10^-6*273.15)/6010 = -3.16 K

you can evaluate the new melting point of ice:

T = Ti + ΔT = 273.15 K - 3.16 K = 269.99 K

4 0
3 years ago
What is the difference between an element and a compound?
stepan [7]
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Gold is made of only one kind of atom, so it's considered an </span>element<span>, but water is a mix of hydrogen and oxygen, so it's a </span>compound<span>.</span>
8 0
3 years ago
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