Answer:
the answer for that is false
Answer:
In order to take steps by humans for controlling the change in climate.
Explanation:
It is important that scientist find out the change which occurs in the climate with the passage of time by performing experiments and also repeat the experiments in order to verify their findings. Due to these experiments, scientists also find out the reasons behind of climate change which enable us to take steps in preventing the change that occurs in the environment. it is also important for scientists to be able to explain how they know that climate has changed over time in order to explain that he is not assuming or making predictions, he has to provide evidence for his statement which is only be possible through experiments.
<span>128 g/mol
Using Graham's law of effusion we have the formula:
r1/r2 = sqrt(m2/m1)
where
r1 = rate of effusion for gas 1
r2 = rate of effusion for gas 2
m1 = molar mass of gas 1
m2 = molar mass of gas 2
Since the atomic weight of oxygen is 15.999, the molar mass for O2 = 2 * 15.999 = 31.998
Now let's subsitute the known values into Graham's equation and solve for m2.
r1/r2 = sqrt(m2/m1)
2/1 = sqrt(m2/31.998)
4/1 = m2/31.998
127.992 = m2
So the molar mass of the unknown gas is 127.992 g/mol.
Rounding to 3 significant figures gives 128 g/mol</span>
Answer:
a) 381.2 g
b) 39916 g
c) 0.0013 lb mol
d) 29.6 g mol
Explanation:
The molecular weight (mw) of a compound is the mass of it per mole, so it's the ratio of the mass (m) per mole (n).
a) The molecular weight of one mol is found at the periodic table. So, for Mg, mw = 24.3 g/mol, for Cl = 35.5 g/mol, so for MgCl2, mw = 24.3 + 2*35.5 = 95.3 g/mol. The g mol is the mass divided by the molecular weight:
g mol = m/mw
4 = m/95.3
m = 381.2 g
b) The pound (lb) is a unity of mass, and the lb mol is a unity of the mass divided by the molecular weight. So, by the periodic table, the molecular weight of C3H8 is 3*12 (of C) + 8*1 (of H) = 44 lb/mol.
lb mol = m/mw
2 = m/44
m = 88 lb
1 lb = 453.592 g
So, m = 88*453.592 = 39916 g
c) The molecular weight of N2 is 2*14 (of N) = 28 lb/mol.
m = 16/453.592 = 0.0353 lb
lb mol = m/mw
lb mol = 0.0353/28
lb mol = 0.0013 lb mol
d) The molecular weight is 2*12 (of C) + 6*1(of H) + 1*16(of O) = 46 g/mol
3 lb = 1360.78 g
g mol = m/mw
g mol = 1360.78/46
g mol = 29.6 g mol
Answer: (3) 15
Explanation: We criss-cross down the oxidation numbers to get the subscripts for the correct formulas. That means the X has an oxidation number of 5. The element with the + oxidation number is always written first so it is +5. Of the groups names, only group 15 has +5 as an oxidation number.