Answer:
Option B, When the cell needs to move a compound against its concentration gradient.
Explanation:
A cell uses active transport when it has to transport substances against the concentration gradient across its membrane.
In active transport additional energy is used (generally provided by energy molecules like ATP) to push the substance across any membrane from low concentration side to high concentration side.
Option B is correct
This one is easy. It's just addition and subtraction. Add the partial pressure of Argon and the partial pressure of Helium:
152 kPa
<u>+305 kPa</u><u>
</u> 457 kPa
Next, subtract the result from the total pressure:
1015 kPa
<u>- 457 kPa</u>
558 kPa
Answer:
What is the amount of energy needed to change 20g of ice at 0°C to steam at 100°C?
A mattress you can fall back on.
Use the formula
q = m·ΔHf
where q = heat energy; m = mass; ΔHf = heat of fusion
q = (20 g)x(334 J/g)
q = 6680 J
Step 2: Heat required to raise the temperature of 0 °C water to 100 °C water
q = mcΔT
q = (20 g)x(4.18 J/g·°C)[(100 °C - 0 °C)]
q = (20 g)x(4.18 J/g·°C)x(100 °C)
q = 8360 J
Heat required to raise the temperature of 0 °C water to 100 °C water = 8360 J
Heat required to convert 100 °C water to 100 °C steam
q = m·ΔHv
where q = heat energy; m = mass; ΔHv = heat of vaporization
q = (20 g)x(2257 J/g)
q = 45140 J
Heat required to convert 100 °C water to 100 °C steam = 45140 J
Total energy required: 6680+8360+45140=60180 Joules
Or practically understanding it: about 20s in a 3000W kettle.
Answer:
[Ne] 3s² 3p²
Explanation:
Silicon atoms have 14 electrons. The ground state electron configuration of ground state gaseous neutral silicon is 1s²2s²2p⁶3s²3p².
Using noble gas shorthand, the electronic configuration is reduced to;
[Ne] 3s² 3p². Ne s the nearest noble gas to silicon, Ne contains 8 electrons, this means there's still 4 more electrons to fill. The s orrbital can only hold 2, hence the reaing two is transferred to the p orbital.
