Answer:
8
Explanation:
Since Xe (xenon) is a noble gas, it has 8 valence electrons. It's outer shell is full and it is a stable element and doesn't like to react. Therefore, since the electron dot diagram is about valence electrons, 8 would be your answer.
The products of a reaction are NaCl and H2O. What does the law of conservation of matter reveal about the reactants in the reaction? A. At least some of the reactants will include NaCl and H2O. B. The reactants will contain only Na, Cl, O, and H in some amounts. C. Na, Cl, O, H, and three other elements were the reactant elements. D. The reactants will have one Na, one Cl, one O, and two H atoms.
Answer:
D
Explanation:
total mass should be equal on both sides
it's a double do displacement reaction
HCl + NaOH --> NaCl + H2O
1. Find the volume ( cm3) of oxygen in: a. 1000cm3 of air b. 50 cm3 of air.
Answer:
A. 210 cm³
B. 10.5 cm³
Explanation:
It is important for us to note that air contains 21% of oxygen, O2. With this idea in mind, let us answer the questions given above.
A. Volume of air = 1000 cm³
Volume of O2 in air =.?
Percentage composition of O2 in air = 21%
Volume of O2 = 21% x 1000
Volume of O2 = 21/100 x 1000
Volume of O2 = 210 cm³
Therefore, the volume of O2 in 1000 cm³ of air is 210 cm³.
B. Volume of air = 50 cm³
Volume of O2 in air =.?
Percentage composition of O2 in air = 21%
Volume of O2 = 21% x 50
Volume of O2 = 21/100 x 50
Volume of O2 = 10.5 cm³
Therefore, the volume of O2 in 50 cm³ of air is 10.5 cm³.
Which of the following chemical reactions is reversible?
A. The burning of wood.
OB. The dehydration of copper sulfate (CuSO4).
O C. The neutralization of an acid.
OD. The freezing of water into ice
Reset Selection
How many molecules are in each sample?
A. 4.9 g H2O
B. 54.4 g N^2
C. 89 g CCI4
D. 11 g C6H12O6
Answer:
To find the number of molecules first find the number of moles.
number of moles (n) = mass / molar mass (M)
then use the formula
N = n × L
where n = number of moles
N = number of entities
L = Avogadro's constant = 6.02 × 10^23entities to find the number of molecules
A. 4.9 g H2O
m = 4.9g
M = (2*1)+(16×1) = 2 + 16 = 18g/mol
n = 4.9/18 = 0.272mol
N = 0.272 × 6.02 × 10^23
= 1.6374*10^23 molecules of H2O
B. 54.4g of N2
m = 54.4g
M(N2) = 14×2 = 28g/mol
n = 54.4/28 = 1.942mol
N = 1.942 * 6.02*10^23
= 1.1690*10^24 molecules of N2
C. 89 g CCI4
m = 89g
M(CCl4) = 12 + (35.5 × 4) = 154g/mol
n = 89/154 = 0.577mol
N = 0.577 × 6.02 × 10^23
= 3.473*10^23 molecules of CCl4
D. 11 g C6H12O6
m = 11g
M(C6H12O6) = (12×6)+(12×1)+(16×6) =
180g/mol
n = 11/180 = 0.0611mol
N = 0.0611 × 6.02×10^23
= 3.678*10^22 molecules of C6H12O6
Hope this helps