Answer:
15.7g
Explanation:
mass percent=mass of element/mass of compound *100
39.34=unknown(x)/40g×100
39.34=5x/2
multiplying both sides by 2,we get
5x=78.68
devide by 5 on both sides
x=15.74g Na
Answer:
The partial pressure of oxygen (pO2) in alveolar air is higher (~13 kPa or 100 mmHg) than that of the venous blood (~5.3 kPa or 40 mmHg) flowing on the other side of the membrane, so oxygen diffuses from the alveoli to blood.
Answer:
1. False
2. False
3. True
4. False
Explanation:
1. CBr4 is more volatile than CCl4 False
The molecular weight of CBr4 is is greater than the CCl4, therefore it has less tendency to escape to the gas phase. Also, the CBr4 has greater London dispersion forces compared to CCl4 since bromine is a larger atom than chlorine.
2. CBr4 has a higher vapor pressure at the same temperature than CCl4 False
For the same reasons as above, the vapor pressure of CBr4 is smaller than the vapor pressure of CCl4
3. CBr4 has a higher boling point than CCl4 True
Again, CBr4 having a molecular weight greater than CCl4 ( 331 g/mol vs 158.2 g/mol) is heavier and less volatile with a higher boiling point than CCl4.
4. CBr4 has weaker intermolecular forces than CCl4 False
Both molecules are non-polar because the dipole moments in C-Cl and C-Br bonds cancel in the tetrahedron. The only possible molecular forces are of the London dispersion type which are temporary and greater for larger atoms.
Nuclear reactions<span> involve a change in the atom's nucleus, they usually produce a different element & c</span>hemical reactions<span> only involve a rearrangement of electrons and do not involve changes in the nuclei.</span>
7.5 × 10¹⁹ Electrons flow through a point in a wire in 3.00 s if there is a constant current of i=4.00a.
Q = I × t------------Equation 1
Where Q = charge flowing through the wire, I = current, t = time
Given: I = 4.00 A, t = 3.00 s
Substitute these values into equation 1
Q = 4.00× 3.00
Q = 12.00 C.
But,
1 electron contains 1.6×10⁻¹⁹ C
therefore,
12.00 C = 12.00/1.6×10⁻¹⁹ electrons
= 7.5 × 10¹⁹ Electrons
To learn more about flow of electrons: brainly.com/question/14805255
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