Answer:
A velocity-time graph shows how velocity changes over time. The sprinter's velocity increases for the first 4 seconds of the race, it remains constant for the next 3 seconds, and it decreases during the last 3 seconds after she crosses the finish line.
Sodium potassium pump is an active pump which transfer sodium and potassium ions across the membrane with the expenditure of energy in the form of ATP.
This kind of pump is generally used in nerve cells.
The pump works against the concentration gradient as the pump moves three Na+ ions outside the cell and two K+ ions inside the cell, though there is a high concentration of Na+ outside the cell and a low concentration of K+ outside the cell.
Number 2 is correct answers
The molar mass of the imaginary compound Z(AX₃)₂ is the sum of the molar mass of Z, A and X.
<h3>How do we calculate molar mass?</h3>
Molar mass of any compound will be calculated by adding the mass of each atoms present in that compound.
Given compound is Z(AX₃)₂, molar mass of the given compound will be calculated as:
Molar mass of Z(AX₃)₂ = Molar mass of Z + molar mass of 2(A) + molar mass of 6(X)
Hence molar mass of Z(AX₃)₂ is the sum of the masses of all atoms.
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Use the atomic mass of potassium, k, 39.1 g/mol, and the formula n = mass / atomic-mass.
Where n is the number of moles.
n = 250.0 g / 39.1 g/mol = 6.3939 mol.
Now multiply by Avogadro number to find the number of atoms:
6.3939 mol * 6.02*1023 atoms/mol = 38.49 * 10^23 atoms = 3.849 * 10^24.
Answer: 3.85*10^24
