<span>The mass of the nail would increase, because the iron is adding oxygen to its chemical composition. This would increase the overall mass. If the mass increases from 23.2g to 24.1g, then the increase would be the difference between the two masses, or 0.9g.</span>
Answer:
B.) The coefficients give the molar ratio of the reactants.
Explanation:
The coefficients represent how many of each molecule are within a reaction. Coefficients are added to make sure the amounts of each element are the same on both sides of the reaction. You can use the coefficients to convert between moles of each molecule. As such, the best answer is B.) because coefficients are what allow you to construct a mole ratio.
About 25 percent of energy in an organism is used by the animal that eats it .
Answer : The photon energy of this light in units of nanometers, (nm) is, 
Solution :
Formula used :
where,
E = energy of photon = 
h = Planck's constant = 
c = speed of light = 
= wavelength = ?
Now put all the given values in the above formula, we get:
conversion used : 
Therefore, the photon energy of this light in units of nanometers, (nm) is,
Answer:
2 mol H
Explanation:
For every 2 mol of NaOH, we're reacting 2 mol of H2O. In order to figure out how many mol of H are needed, it needs to be set up stochiometrically. Starting off with the given value, 1 mol of NaOH, we can then make a mol to mol ratio. For 2 mol of NaOH, we have 2 mol of H2O. For every 2 mol of H2O, we have 4 mol of H (this is because we are multiplying the coefficient by the subscript: 2 × 2). Now, we can solve for our answer.
1 mol NaOH × (2 mol H₂O / 2 mol NaOH) × (4 mol H / 2 mol H₂O)
= 2 mol H
Thus, we get 2 mol of H are needed to completely react 1 mol of NaOH.
