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zhenek [66]
3 years ago
11

Which of the following apply to the property of hardness. Select all that apply.

Chemistry
2 answers:
Roman55 [17]3 years ago
7 0

The correct statements are:

Hardness is a physical property.

Friedrich Mohs developed the standard hardness scale.

Diamond can scratch quartz.

k0ka [10]3 years ago
3 0
I’m figuring this one out right now
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A gas mixture contains HBr, NO2, and C2H6 at STP.If a tiny hole is made in the container, which gas will effuse fastest?Which ga
MakcuM [25]

Explanation:

Molar mass of HBr = 81 g/mol

Molar mass of nitrogen dioxide gas = 46 g/mol

Molar mass of ethane = 30 g/mol

Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}

So, the gas with least molar mass will effuse out fastest from the container and that is ethane gas.

The formula for average kinetic energy is:

K.E=\frac{3}{2}kT

where,

k = Boltzmann’s constant = 1.38\times 10^{-23}J/K

T = temperature = 273.15 K ( at STP)

As we can see from the formula that kinetic energy depends upon only temperature of the gas molecule.

So, from this we can say that all the gas molecules have the same average kinetic energy at this temperature.

5 0
4 years ago
Check all that apply.
xxMikexx [17]

Answer:

DO NOT TASTE IT, but all the rest are correct

Explanation:

8 0
3 years ago
Read 2 more answers
A chemist dissolves 484 .mg of pure perchloric acid in enough water to make up 240.mL of solution. Calculate the pH of the solut
sdas [7]

Answer:

1.70

Explanation:

The molar mass of perchloric acid is 100.46 g/mol. The moles corresponding to 484 mg (0.484 g) are:

0.484 g × (1 mol/100.46 g) = 4.82 × 10⁻³ mol

4.82 × 10⁻³ moles are dissolved in 240 mL (0.240 L) of solution. The molar concentration of perchloric acid is:

4.82 × 10⁻³ mol/0.240 L = 0.0201 M

Perchloric acid is a strong monoprotic acid, that is, it dissociates completely, so [H⁺] = 0.0201 M.

The pH is:

pH = -log [H⁺] = -log 0.0201 = 1.70

8 0
3 years ago
What happens with the energy radiated from the Sun once it gets to Earth? (mark ALL correct answers)
FrozenT [24]

Answer:

Absorbed by the surface of earth

Explanation:

Mark brainliest

3 0
2 years ago
How does mg2+ block the effect of extracellular calcium on neurotransmitter release?
svetlana [45]
<span>Magnesium is a strong anode than calcium. So, Mg will be oxidized into Mg2+. So instead of having Ca being the reducing agent, Mg will takes its place. That's how the "Blocking" occur.
</span><span>Without Ca2+, no neurotransmitter was released because the exocytosis of the synaptic vesicles is dependent upon Ca2+.
</span>So, when magnesium is added to the extracellular fluid it blocks the calcium channels and inhibits the release of <span>neurotransmitter.</span>
5 0
3 years ago
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