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White raven [17]
2 years ago
14

Define what is halflife​

Chemistry
1 answer:
zhuklara [117]2 years ago
8 0

Half-life is the time it takes for a substance to lose half of its pharmacological, physiological, or radiological activity.

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Carbon dioxide and helium which has a higher van der waals force of attraction between molecules ​
raketka [301]

Answer:

Carbon dioxide  

Explanation:

Neither helium nor carbon dioxide has a molecular dipole, so their strongest van der Waals attractive forces are London forces.

Helium is a small spherical atom with only a two electrons, so its atoms have quite weak attractions to each other.

CO₂ is a large linear molecule. It has more electrons than helium, so the attractive forces are greater. Furthermore, the molecules can align themselves compactly side-by-side and maximize the attractions (see below).

For example. CO₂ becomes a solid at -78 °C, but helium must be cooled to -272 °C to make it freeze (that's just 1 °C above absolute zero).

7 0
2 years ago
The ksp of calcium carbonate, caco3, is 3.36 × 10-9 m2. calculate the solubility of this compound in g/l.
maw [93]
CaCO₃ partially dissociates in water as Ca²⁺ and CO₃²⁻. The balanced equation is,
                       CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)
Initial                Y                   -                 -
Change           -X                  +X              +X
Equilibrium      Y-X                 X                X

Ksp for the CaCO₃(s) is 3.36 x 10⁻⁹ M²

                Ksp = [Ca²⁺(aq)][CO₃²⁻(aq)]
3.36 x 10⁻⁹ M² = X * X
3.36 x 10⁻⁹ M² = X²
                    X = 5.79 x 10⁻⁵ M

Hence the solubility of CaCO₃(s) = 5.79 x 10⁻⁵ M
                                                     = 5.79 x 10⁻⁵ mol/L

Molar mass of CaCO₃ = 100 g mol⁻¹

Hence the solubility of CaCO₃ = 5.79 x 10⁻⁵ mol/L x 100 g mol⁻¹
                                                 = 5.79 x 10⁻³ g/L

7 0
3 years ago
Can someone tell me the parts and the functions ?
Delvig [45]
Each hemisphere has four sections, called lobes: frontal, parietal, temporal and occipital. Each lobe controls specific functions. For example, the frontal lobe controls personality, decision-making and reasoning, while the temporal lobe controls, memory, speech, and sense of smell.
3 0
3 years ago
Read 2 more answers
NEED HELP ASAP!!!!!!!!!!!!!!!!!!!!!!
Paraphin [41]
<h2>Answer:  C) 1s²2s²2p⁶</h2>

<h3>Explanation:</h3>

A noble gas has 8 electrons between the p and s orbitals of the outer shell. Helium is the exception because it only has two electrons.

<h3>                       ∴  1s²2s²2p⁶ is the noble gas (neon)</h3>

7 0
2 years ago
4. Write the chemical equation for the reaction that occurs when baking soda (NaHCO3) is
aev [14]

Answer: HCl+NaHCO₃=NaCl+CO₂+H₂O

Explanation:

3 0
3 years ago
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