Answer:
7 is the only basic number on a pH scale
Answer: Option (3) is the correct answer.
Explanation:
When there is a negative charge on an atom then we add the charge with the number of electrons. Whereas when there is a positive charge on an atom then we subtract the charge from the number of electrons.
Atomic number of chlorine is 17. So, number of electrons present in 
is 17 + 1 = 18 electrons.
Atomic number of cobalt is 27. So, number of electrons present in 
is 27 - 4 = 23 electrons.
Atomic number of iron is 26. So, number of electrons present in 
is 26 - 2 = 24 electrons.
Atomic number of vanadium is 23. So, number of electrons present in V is 23 electrons.
Atomic number of scandium is 21. So, number of electrons present in 
is 21 + 2 = 23 electrons.
Thus, we can conclude that out of the given species, has the greatest number of electrons.
Answer:
10.000 grams
Explanation:
For the first law of thermodynamics, the energy must be conserved, that means that the energy in form of heat (Q) must be equal to the sum of work (W) and internal energy(ΔU) :
Q = W + ΔU
ΔU depends on the temperature and W in the variation of pressure and volume. Q depends on the temperature, but also the mass. So, there is the same temperature, ΔU is equal for both reaction, if there is no work done, the heat must be equal for both of them. So the mass such be the same.
<span>H2O2
First, let's determine how many moles of hydrogen and oxygen atoms we have. Start by looking up the atomic weights of those elements:
Atomic weight hydrogen = 1.00794
Atomic weight oxygen = 15.999
Moles hydrogen = 1.33 g / 1.00794 g/mol = 1.319522987 mol
Moles oxygen = 21.3 g / 15.999 g/mol = 1.331333208 mol
We now have a ratio of 1.319522987 : 1.331333208 and we want a ratio of small integers that is close. Start by dividing all the numbers in the ratio by the smallest value, giving:
1 : 1.008950371
This ratio is acceptably close to 1:1 so I assume the formula is of the form HnOn where n is a small integer. Let's initially assume that n is 1, so the mass would be
1.00794 + 15.999 = 17.00694
Obviously 17 is far smaller than 34.1. So let's divide 34.1 by 17.00694 and see what n should be:
34.1 / 17.00694 = 2.005063815
So the formula we want is H2O2, which is hydrogen peroxide.</span>
