Answer:
i got ddoxed by skai jackson
Explanation:
it sucked
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
Calculate the mass (in grams) of hydrogen gas produced when 33.61 g of
diborane (B2H) reacts with excess water.
B Holg) + 6H2O(1)→ 2 H3B03(s) + 6H2(g)
Only enter numerical value without units.
Answer:
14.40g of H2
Explanation:
The balanced equation for the reaction is given below:
B2H6(g) + 6H2O(l) → 2H3BO3(s) + 6H2(g)
Next, we shall determine the mass of B2H6 that reacted and the mass of H2 produced from the balanced equation. This is illustrated below:
Molar mass of B2H6 = (2x11) + (6x1) = 28g/mol
Mass of B2H6 from the balanced equation = 1 x 28 = 28g
Molar mass of H2 = 2x1 = 2g/mol
Mass of H2 from the balanced equation = 6 x 2 = 12g
From the balanced equation above,
28g of B2H6 reacted to produce 12g of H2.
Finally, we shall determine the mass of H2 produced when 33.61g of B2H6 reacted with excess water. This can be obtained as follow:
From the balanced equation above,
28g of B2H6 reacted to produce 12g of H2.
Therefore, 33.61g of B2H6 will react to produce = (33.61 x 12)/28 = 14.40g of H2.
Therefore, 14.40g of H2 were produced from the reaction.
To draw a Lewis structure for a polyatomic ion, begin by calculating A, the available electrons, and N, the needed electrons. What is N for CIO3-, the chlorate ion?
Answer:
N for chlorate ion is one
Explanation:
Because N is the number of electrons needed to form octet structure causing a negative charge of one, since it already has 25valence electrons
Answer: 26
Correct Answer
Which best explains why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction?
A)The fireworks produce colors.
B)The fireworks give off heat.
C)Igniting the fireworks requires energy
D)Igniting the fireworks makes an odor.
Answer:B
Explanation:
TOOK DA TEST
As the firework releases heat, it is considered as exothermic reaction. The correct option is B.
What is exothermic reaction?An exothermic reaction is one in which the energy required to break bonds in the reactants is less than the energy released when new bonds form in the products.
Energy is constantly released during an exothermic reaction, often in the form of heat. Exothermic reactions characterize all combustion reactions.
Endothermic reactions are chemical reactions that produce products by absorbing heat energy from their surroundings.
Exothermic reactions are important in forensic science, particularly in the investigation of fires and explosions.
Endothermic refers to a chemical reaction that requires heat and results in cooling of the surroundings.
As fireworks are releasing energy in the form of heat, it can be called as an exothermic reaction.
Thus, the correct option is B.
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Scientific evidence shows that Earth's diameter, and thus overall size, does.
not change. This evidence goes against which two theories?
A. Expanding Earth
B. Plate tectonics
U
C. Contracting Earth
D. Continental drift
SUBMIT
Answer:
Expanding earth and contracting earth
Explanation:
Answer:
A and C
Explanation:
How many grams of carbon dioxide does a hummingbird emit daily?
Answer:
3.5 g CO2
Explanation:
A hummingbird emits up to 3.5 grams of CO2 a day.
Equation:7.9 x 10‒2mol CO2x (44.01 g CO2/ 1 mol CO2)
=3.5 grams
Hope this helps!
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
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
PLEASE HELP!
Why is phosphorus diamagnetic.
Answer:
FROM the magnetic point of view, phosphorus is an extremely interesting
substance because of its allotropic modifications. The ordinary forms are
the yellow (or white) and the red varieties. X-ray investigations indicate
that probably yellow phosphorus is analogous with the cubic forms of antimony and arsenic; and red phosphorus with monoclinic antimony and
arsenic (Mellor, 1928). The conclusions of different workers on the structure of red phosphorus are not in agreement. There is also Bridgman's black
phosphorus which is probably hexagonal (Linck and lung, 1925). Natta
and Passerini (1930) have studied the crystal structure of white phosphorus.
This substance when condensed at the temperature of liquid ammonia is
cubic. Atomic positions however are yet undetermined. Another and noncubic form is obtained by condensation at liquid-air temperatures. It is
thus clear that most likely white phosphorus is cubic in structure with a
probable superposition of another lattice.
The evidence from Raman effect also points to the same conclusion.
Bhagavantam (1930) investigated the Raman effect of white phosphorus in
the solid state. The characteristic frequencies obtained by him are 607, 468
and 374. Since the phosphorus molecule is known to contain 4 atoms,
Bhagavantam (1930) has shown that the tetrahedral structure fits the results
satisfactorily since such a structure would give only three frequencies. But
for the particular law of forces adopted, the frequencies should have the
ratio 2: 2: 1 but the observed frequencies deviate considerably.
Phosphorus is a really intriguing element. because of the allotropic changes to the material.
Why phosphorus is dimagnetic?Red phosphorus is likely akin to monoclinic antimony, while yellow phosphorus is probably similar to the cubic forms of antimony and arsenic.
There is disagreement among the findings of many researchers regarding the structure of red phosphorus. Additionally, Bridgman's black It is presumably hexagonal, phosphorous (Linck and lung, 1925). Natta and Passerini (1930) have investigated the white phosphorus crystal structure.
Condensed from this material at liquid ammonia temperature is cubic. However, the locations of the atoms are still unknown. Condensation at liquid air temperatures yields a different, noncubic shape.
Therefore, Phosphorus is a really intriguing element. because of the allotropic changes to the material.
To learn more about phosphorus, refer to the link:
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14.
Two jewelers were asked to measure the
mass of a gold nugget. The true mass of the
nugget is 0.856 grams (g). Each jeweler took
three measurements. The average of the
three measurements was reported as the
"official” measurement with the following
results:
Jeweler A: 0.863 g, 0.869 g, 0.859 g
Jeweler B: 0.875 g, 0.834 g, 0.858 g
Which jeweler's official measurement was
more accurate? Which jeweler's measure-
ments were more precise? In each case, what
was the error and percent error in the official
measurement?
Answer:
Jeweler B = more accurate
Jeweler A = more precise
Error:
0.008, 0
% error :
0.934% ; 0
Explanation:
Given that:
True mass of nugget = 0.856
Jeweler A: 0.863 g, 0.869 g, 0.859 g
Jeweler B: 0.875 g, 0.834 g, 0.858 g
Official measurement (A) = 0.863 + 0.869 + 0.859 = 2.591 / 3 = 0.864
Official measurement (B) = 0.875 + 0.834 + 0.858 = 2.567 / 3 = 0.8556
Accuracy = closeness of a measurement to the true value
Accuracy = true value - official measurement
Jeweler A's accuracy :
0.856 - 0.864 = - 0.008
Jeweler B's accuracy :
0.856 - 0.856 = 0.00
Therefore, Jeweler B's official measurement is more accurate as it is more close to the true value of the gold nugget.
However, Jeweler A's official measurement is more precise as each Jeweler A's measurement are closer to one another than Jeweler B's measurement which are more spread out.
Error:
Jeweler A's error :
0.864 - 0.856 = 0.008
% error =( error / true value) × 100
% error = (0.008/0.856) × 100% = 0.934%
Jeweler B's error :
0.856 - 0.856 = 0 ( since the official measurement as been rounded to match the decimal representation of the true value)
% error = 0%