Answer:
B. Ca2+ import into the ER because it has the steeper concentration gradient
Explanation:
ΔGt = RT㏑(C₂/C₁)
where ΔGt is the free energy change for transport; R = 8.315 J/mol; T = 298 K; C₂/C₁ is ratio of concentrations inside and outside each organelle.
For Ca²⁺ import
ΔGt = 8.315 J/mol * 298 K * ㏑(10⁻³/10⁻⁷)
ΔGt= 3.42 kJ/mol
For H⁺ import
ΔGt = 8.315 J/mol * 298 K * ㏑ (10⁻⁴/10⁻⁷)
ΔGt = 2.73 kJ/mol
From the above values, ΔGt is greater for Ca²⁺ import because it has a steeper concentration gradient
Answer:
The total energy, i.e. sum of kinetic and potential energy, is constant.
i.e. E = KE + PE
Initially, PE = 0 and KE = 1/2 mv^2
At maximum height, velocity=0, thus, KE = 0 and PE = mgh
Since, total energy is constant (KE converts to PE when the ball is rising),
therefore, KE = PE
or, 1/2 mv^2 = mgh
or, h = v^2 /2g = 13^2 / (2x9.8) = 8.622 m
Hope this helps.
Nonane (b) has the highest melting point.
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A caveat: I'm assuming that we're dealing with the straight-chain isomers of these alkanes (specifically pentane and nonane). The straight-chain isomer of pentane (<em>n</em>-pentane, CH3-[CH2]3-CH3) has a melting point of -129.8 °C; the straight-chain isomer of nonane (<em>n-</em>nonane, CH3-[CH2]7-CH3) has a melting point of -53.5 °C. The pattern holds as you go down (or up): The more carbon atoms, the higher the melting point. So, in decreasing order of melting points here, you'd have the following: nonane > pentane > butane > ethane.
However, one structural isomer of pentane, neopentane, has a melting point of -16.4 °C, which is <em>higher </em>that the melting point of <em>n</em>-nonane despite neopentane having the same molecular formula as its straight-chain isomer. Of course, you're not to blame for coming up with this question; this is just some extra info to keep in mind.
In general chemistry, isomers are two or more elements that have the same number of protons but differ in mass number. In organic chemistry, the compounds are cis or trans isomers if they have the same chemical formula, but differ in the placement of functional groups based on molecular geometry. Cis isomer is when two like functional groups are on the same side of the molecules, while trans isomer is when the like functional groups are on opposite sides.
The cis-trans isomers are shown in the picture. As you can see, in the cis isomer, the methane functional group are both in the same side. Same as well with the hydrogen atoms. On the other hand, these functional groups are opposite to each other in the trans isomer.
Answer:
12.213 minutes will be taken for 120 g-Thalium-208 to decay to 75 grams.
Explanation:
Radioactive isotopes decay exponentially in time, the mass of the isotope (
), in grams, is described by the formula in time (
), in minutes:
(1)
Where:
- Initial mass of the isotope, in grams.
- Time constant, in minutes.
In addition, the time constant associated with the isotope decay can be described in terms of half-life (
), in minutes:
(2)
If we know that
,
and
, then the time taken by the isotope is:






12.213 minutes will be taken for 120 g-Thalium-208 to decay to 75 grams.