Answer:
Active transport by the Na+-K+ pump
Explanation:
Active transport by the Na+-K+ pump
Maintenance (and restoration) of the resting ion concentrations depends on the Na+-K+ pump. Once gated ion channels are closed, the combined action of the pump and ion leakage (particularly that of K+) establishes a resting membrane potential in a typical neuron of around âˆ'70 mV.
Tin metal reacts with hydrogen fluoride to produce tin(II) fluoride and hydrogen gas according to the following balanced equation.
Sn(s)+2HF(g)→SnF2(s)+H2(g)
Sn(s)+2HF(g)→
SnF
2
(s)+
H
2
(g)
How many moles of hydrogen fluoride are required to react completely with 75.0 g of tin?
Step 1: List the known quantities and plan the problem.
Known
given: 75.0 g Sn
molar mass of Sn = 118.69 g/mol
1 mol Sn = 2 mol HF (mole ratio)
Unknown
mol HF
Use the molar mass of Sn to convert the grams of Sn to moles. Then use the mole ratio to convert from mol Sn to mol HF. This will be done in a single two-step calculation.
g Sn → mol Sn → mol HF
Step 2: Solve.
75.0 g Sn×1 mol Sn118.69 g Sn×2 mol HF1 mol Sn=1.26 mol HF
75.0 g Sn×
1
mol Sn
118.69
g Sn
×
2
mol HF
1
mol Sn
=1.26 mol HF
Step 3: Think about your result.
The mass of tin is less than one mole, but the 1:2 ratio means that more than one mole of HF is required for the reaction. The answer has three significant figures because the given mass has three significant figures.
Answer: In Arizona, climate change is already making deadly heat waves, droughts and wildfires across the state worse. These impacts have real costs on Arizonans' health and economy, including heat-related deaths, higher electricity bills, crop losses and more.
Explanation:
https://www.edf.org/climate/costofinaction- this is where I gathered this info. Not mine. But I hope it helps!
The concentration after dilution is 1.4%.
We are aware that concentration and volume are related to each other by the formula -
=
, where we have initial concentration and volume on Left Hand Side and final concentration and volume on Right Hand Side.
Keep the values to calculate final concentration.
= (53.5 × 5.4)/205.0
Performing multiplication on Right and Side
= 288.9/205.0
Performing division on Right Hand Side
= 1.4%
Hence, the final concentration is 1.4%.
Learn more about concentration -
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The complete question is -
A 53.5 mL sample of an 5.4 % (m/v) KBr solution is diluted with water so that the final volume is 205.0 mL.
Calculate the final concentration and express your answer to two significant figures and include the appropriate units.