Answer:
A. 1.88 mol H₂
B. 182 g Al₂(SO₄)₃
C. 54.8%
Explanation:
2 Al + 3 H₂SO₄ ⇒ Al₂(SO₄)₃ + 3 H₂
A. Convert grams of Al to moles. The molar mass is 26.98 g/mol.
(33.8 g)/(26.98 g/mol) = 1.253 mol Al
Use stoichiometry to convert moles of Al to moles of H₂. Looking at the equation, you can see that for every 2 mol of Al consumed, 3 moles of H₂ is produced. Use this relationship.
(1.253 mol Al) × (3 mol H₂)/(2 mol Al) = 1.879 mol H₂
You will produce 1.88 mol of H₂ gas.
B. Again, use stoichiometry. For every 3 moles of H₂SO₄ consumed, 1 mole of Al₂(SO₄)₃ is produced.
(1.60 mol H₂SO₄) × (1 mol Al₂(SO₄)₃/3 mol H₂SO₄) = 0.533 mol Al₂(SO₄)₃
Convert moles of Al₂(SO₄)₃ to grams. The molar mass is 342.15 g/mol.
(0.533 mol) × (342.15 g/mol) = 182.48 g Al₂(SO₄)₃
You will produce 182 g of Al₂(SO₄)₃.
C. Calculate percent yield by dividing the actual yield by the theoretical yield. Multiply by 100%.
(100.0/182.48) × 100% = 54.8%
The percent yield is 54.8%.
A sample of an unknown substance has a mass of 0.158kg. If 2,520.0 j of heat is required to heat the substance from 32.0C to 61.0C what is the specific heat of the substance
Convert 120 degrees F to K.
[?]K
Answer:
322
Explanation:
This is easy
A sample of gas occupies a volume of 7.50 L at 0.988 atm and 301 K. At what temperature is the volume of the gas 4.00 L if the pressure is kept constant.
Answer:
160.53L
Explanation:
Since Pressure is kept constant we can use charles law
V1/T1 =V2/T22 Points
Which element has the fewest valence electrons?
A. Magnesium (Mg)
B. Neon (Ne)
C. Chlorine (CI)
O D. Silicon (Si)
SUSNE
Answer:
A. Magnesium (Mg)Explanation:
As the elements go left in the periodic table, they have fewer valence electrons.
Magnesium has 2 valence electrons.
Neon has 8 valence electrons.
Chorine has 7 valence electrons.
Silicon has 4 valence electrons.
Magnesium has the fewest valence electrons.
Answer:
A
Explanation:
Magnesium
Given the information about each pair of acids fill in the correct answer.
a. Acid A has a lower % ionization than B:_______ is a stronger acid.
b. Acid B has a larger K_a than acid A._______ will have a larger percent ionization.
c. A is a stronger acid than B. Acid B will have________ percent ionization than A.
Answer:
a. Acid B
b. Acid B
c. lower
Hope this helps you
The element nitrogen would be expected to form covalent bond(s) in order to obey the octet rule. Use the octet rule to predict the formula of the compound that would form between nitrogen and hydrogen , if the molecule contains only one nitrogen atom and only single bonds are formed. Formula:
Answer:
The compound formula will be "NF₃". The further explanation is given below.
Explanation:
Nitrogen seems to have an electrical structure consisting of 1S², 2S² as well as 3S² and it requires three electrons to fulfill or conclude the octet. This will, therefore, form three bonds (covalent). Even though only single nitrogen has been present, that can only represent a single bond including fluorine. Therefore the methodology for something like the compound would be NF₃.So that the above would be the right answer.
Using the determined equivalence point from question 2 and the balanced reaction of acetic acid and sodium hydroxide, calculate the molarity of the acetic acid in your hot sauce packet.
Equivalance point is 3.0 mL NaOH, 0.6 g hot sauce, 0.1 M NaoH.
Answer:
Molarity of the packet is 0.5M
Explanation:
In the reaction of acetic acid with NaOH:
CH₃COOH + NaOH → CH₃COO⁻ + H₂O + Na⁺
1 mole of acetic acid reacts with 1 mole of NaOH.
When you are titrating the acid with NaOH, you reach equivalence point when moles of acid = moles of NaOH.
Moles of NaOH are:
3.0mL = 3.0x10⁻³L ₓ (0.1 mol / L) = 3.0x10⁻⁴ moles of NaOH = moles of CH₃COOH.
Now, you find the moles of acetic acid in the hot sauce packet. But molarity is the ratio between moles of the acid and liters of solution.
As you don't know the volume of your packet, you can assume its density as 1g/mL. Thus, volume of 0.6g of hot sauce is 0.6mL = 6x10⁻⁴L.
And molarity of the packet is:
3.0x10⁻⁴ moles acetic acid / 6x10⁻⁴L =
0.5MOrganic chemistry too eazy but why 90% students avoid ?
Answer:
because it covers a large area as there are more then 1 lakh compounds of organic chemistry.
Calculate the grams of solute needed to prepare 107 mL of a 2.75 M magnesium
chloride solution
Your Answer:
Answer
Answer: 28.02 g
Explanation:
The M stands for molarity. It is moles of solute/liters of solution. We can use the molarity to convert liters to mL, then make a proportion to find the grams.
[tex]\frac{2.75 mol}{L} *\frac{1L}{1000mL} =\frac{2.75 mol}{1000mL}[/tex]
Now that we have molarity in moles and mL, we can use the 107mL to get moles.
[tex]\frac{2.75moles}{1000mL} *107mL=0.29425mol[/tex]
We would multiply moles by molar mass to get grams. The molar mass of magnesium chloride is 95.211 g/mol.
[tex]0.29425mol*\frac{95.211g}{mol} =28.02g[/tex]
Sort the resources into the correct categories.
are replaced by natural processes
Renewable Resources
Nonrenewable Resources
cannot be replaced in a short time
are used more quickly than replaced
have fixed amounts
are considered unlimited
are replaced faster than used
Intro
✓ Done
Answer:
Renewable Resources: are considered unlimited, are replaced faster than used.
Nonrenewable Resources: are used more quickly than replaced, have fixed amounts, cannot be replaced in a short time.
Explanation:
Renewable resources are natural resources that are able to naturally regenerate themselves, hence, they are considered to be unlimited. They are usually replaced faster than they are used because they have a short regeneration time. A good example is the solar energy.
Nonrenewable resources are those natural resources that cannot naturally regenerate and when they do, it takes a very long time (usually millions of years). They are therefore used at a much faster rate than they are being replaced and their natural deposits are more or less fixed due to the long regeneration time. A good example is the crude oil deposit.
Hence:
Renewable Resources: are considered unlimited, are replaced faster than used.
Nonrenewable Resources: are used more quickly than replaced, have fixed amounts, cannot be replaced in a short time.
Answer: !
Explanation:
g what would happen to the solubility of a gas in a solution if the pressure above the solution is increased
Answer: The solubility of gas increases in a solution if the pressure above the solution is increased
Explanation:
Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.
To calculate the molar solubility, we use the equation given by Henry's law, which is:
[tex]C=K_H\times p[/tex]
where,
C = solubility
[tex]K_H[/tex] = Henry's constant
p = partial pressure
As the solubility is directly proportional to the pressure, thus increasing the pressure increases the solubility.
The complete combustion of ethanol, C2H5OH(l), to form H2O(g) and CO2(g) at constant pressure releases 1235 kJ of heat per mole of C2H5OH.
Write a balanced equation for this reaction.
Express your answer as a chemical equation. Identify all of the phases in your answer.
How much heat is absorbed when 52.39 H2O(l) at 100°C and 101.3 kPa is converted to steam at 100°C? (The molar heat of vaporization of water is
40.7 k/mol.)
2.09 x 1020
O 2.31% 10110
O 1.18 x 102 103
O 1.11% 1021)
Calculate the volume of 0.500 M C2H3O2H and 0.500 M C2H3O2Na required to prepare 0.100 L of pH 5.00 buffer with a buffer strength of 0.100 M. The pKa of C2H3O2H is 4.75.
Answer:
You require 12.8mL of the 0.500M C₂H₃O₂Na and 7.2mL of the 0.500M C₂H₃O₂H
Explanation:
It is possible to obtain pH of a weak acid using H-H equation:
pH = pKa + log₁₀ [A⁻] / [HA]
For the buffer of acetic acid/acetate, the equation is:
pH = pKa + log₁₀ [C₂H₃O₂Na] / [C₂H₃O₂H]
Replacing:
5.00 = 4.75 + log₁₀ [C₂H₃O₂Na] / [C₂H₃O₂H]
1.7783 = [C₂H₃O₂Na] / [C₂H₃O₂H] (1)
Buffer strength is the concentration of the buffer, that means:
0.1M = [C₂H₃O₂Na] + [C₂H₃O₂H] (2)
Replacing (2) in (1):
1.7783 = 0.1M - [C₂H₃O₂H] / [C₂H₃O₂H]
1.7783 [C₂H₃O₂H] = 0.1M - [C₂H₃O₂H]
2.7783 [C₂H₃O₂H] = 0.1M
[C₂H₃O₂H] = 0.036MAlso:
[C₂H₃O₂Na] = 0.1M - 0.036M
[C₂H₃O₂Na] = 0.064MThe moles of both compounds you require is:
[C₂H₃O₂Na] = 0.1L × (0.064mol / L) = 0.0064moles
[C₂H₃O₂H] = 0.1L × (0.036mol / L) = 0.0036moles
Your stock solutions are 0.500M, thus, volume of both solutions you require is:
[C₂H₃O₂Na] = 0.0064moles × (1L / 0.500M) = 0.0128L = 12.8mL
[C₂H₃O₂H] = 0.0036moles × (1L / 0.500M) = 0.0072mL = 7.2mL
You require 12.8mL of the 0.500M C₂H₃O₂Na and 7.2mL of the 0.500M C₂H₃O₂HThe Ksp of calcium sulfate, CaSO4, is 9.0 × 10-6. What is the concentration of CaSO4 in a saturated solution? A. 3.0 × 10-3 Molar B. 9.0 × 10-3 Molar C. 3.0 × 10-6 Molar D. 9.0 × 10-6 Molar
Answer: The concentration of [tex]CaSO_4[/tex] in a saturated solution is [tex]3.0\times 10^{-3}M[/tex]
Explanation:
Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]
The equation for the ionization of [tex]CaSO_4[/tex] is given as:
[tex]K_{sp}[/tex] of [tex]CaSO_4[/tex] = [tex]9.0\times 10^{-6}[/tex]
By stoichiometry of the reaction:
1 mole of [tex]CaSO_4[/tex] gives 1 mole of [tex]Ca^{2+}[/tex] and 1 mole of [tex]SO_4^{2-}[/tex]
When the solubility of [tex]CaSO_4[/tex] is S moles/liter, then the solubility of [tex]Ca^{2+}[/tex] will be S moles\liter and solubility of [tex]SO_4^{2-}[/tex] will be S moles/liter.
[tex]K_{sp}=[Ca^{2+}][SO_4^{2-}][/tex]
[tex]9.0\times 10^{-6}=[s][s][/tex]
[tex]9.0\times 10^{-6}=s^2[/tex]
[tex]s=3.0\times 10^{-3}M[/tex]
Thus concentration of [tex]CaSO_4[/tex] in a saturated solution is [tex]3.0\times 10^{-3}M[/tex]
g The "Coulomb barrier" is defined to be the electric potential energy of a system of two nuclei when their surfaces barely touch. The probability of a nuclear reaction greatly increases if the energy of the system is above this barrier. What is the Coloumb barrier (in MeV) for the absorption of an alpha particle by a lead-208 nucleus
Answer:
The Coulomb Barrier U is 25.91 MeV
Explanation:
Given that:
Atomic Mass of lead nucleus A = 208
atomic mass of an alpha particle A = 4
Radius of an alpha particle [tex]R_\alpha = R_o A^{^{\dfrac{1}{3}}[/tex]
where;
[tex]R_\alpha = 1.2 \times 10 ^{-15} \ m[/tex]
[tex]R_\alpha = R_o A^{^{\dfrac{1}{3}}[/tex]
[tex]R_\alpha = 1.2 \times 10 ^{-15} \ m \times (4) ^{^{\dfrac{1}{3}}[/tex]
[tex]R_\alpha = 1.905 \times 10^{-15} \ m[/tex]
Radius of the Gold nucleus
[tex]R_{Au}= R_o A^{^{\dfrac{1}{3}}[/tex]
[tex]R_{Au}= 1.2 \times 10 ^{-15} \ m \times (208) ^{^{\dfrac{1}{3}}[/tex]
[tex]R_{Au} = 7.11 \times 10^{-15} \ m[/tex]
[tex]R = R_\alpha + R_{Au}[/tex]
[tex]R = 1.905 \times 10^{-15} \ m + 7.11 \times 10^{-15} \ m[/tex]
[tex]R = 9.105 \times 10 ^{-15} \ m[/tex]
The electric potential energy of the Coulomb barrier [tex]U = \dfrac{Ke \ q_{\alpha} q_{Au}}{R}[/tex]
[tex]U = \dfrac{8.99 \times 10^9 \ N.m \ ^2/C ^2 \ \times 2 ( 82) \times \(1.60 \times 10^{-19} C \ \ e } {9.105 \times 10^{-15} \ m }[/tex]
U = 25908577.7eV
U = 25.908577 × 10⁶ eV
U = 25.91 MeV
The Coulomb Barrier U is 25.91 MeV
For the reaction Ca(s)+Cl2(g)→CaCl2(s) calculate how many grams of the product form when 14.4 g of Ca completely reacts. Assume that there is more than enough of the other reactant.
Answer:
[tex]m_{CaCl_2}=39.96gCaCl_2[/tex]
Explanation:
Hello,
In this case, for the undergoing reaction, we can compute the grams of the formed calcium chloride by noticing the 1:1 molar ratio between calcium and it (stoichiometric coefficients) and using their molar mass of 40 g/mol and 111 g/mol by using the following stoichiometric process:
[tex]m_{CaCl_2}=14.4gCa*\frac{1molCa}{40gCa} *\frac{1molCaCl_2}{1molCa} *\frac{111gCaCl_2}{1molCaCl_2}\\ \\m_{CaCl_2}=39.96gCaCl_2[/tex]
Clearly, chlorine is not used since it is said there is enough for the reaction to go to completion.
Best regards.
Which of the following cannot have hydrogen bonds? Select one: A. NH3 B. H2O C. HF D. CH3NH2 E. Which of the following cannot have hydrogen bonds? Select one: A. NH3 B. H2O C. HF D. CH3NH2 E. HCl
Answer:
E. HCl
Explanation:
Cl atom does not have enough electronegativity to make enough positive charge on H.
HCl is the compound which doesn't have hydrogen bonds. This is because of
the higher size of the chlorine atom.
There is no hydrogen bond because of the high size of the chlorine.
Chlorine have electrons with a very low density. It is also very
electronegative which explains why the formation of hydrogen bonds in the
compound HCl is not possible.
Instead, HCl has covalent bonds in which electron is shared between the
hydrogen and chlorine to achieve a stable configuration.
Read more on https://brainly.com/question/10462894
What is the mass number of an atom with 24 protons and 30 neutrons?
Answer:
54
Explanation:
Mass number = protones + neutrons
Mass number = 24 + 30
Mass number = 54
If iron metal reacts with an aqueous solution of silver nitrate and zinc reacts with an aqueous solution of iron sulfate, rank these three metals Fe Zn Ag in order of decreasing reactivity.
Answer:
yes!you are right a cloudy formation will be formed when they will react.its because if nitrogen.
Lead can be prepared from galena [lead(II) sulfide] by first heating with oxygen to form lead(II) oxide and sulfur dioxide. Heating the metal oxide with more galena forms the metal and more sulfur dioxide. Write a balanced equation for the overall reaction by adding the balanced equations for the two steps.
Answer:
2 PbS(s) + 1.5 O₂(g) + PbO(s) ⇒ 2 SO₂(g) + 3 Pb(s)
Explanation:
Lead can be prepared from galena [lead(II) sulfide] by first heating with oxygen to form lead(II) oxide and sulfur dioxide. The corresponding chemical equation is:
PbS(s) + 1.5 O₂(g) ⇒ PbO(s) + SO₂(g)
Heating the metal oxide with more galena forms the metal and more sulfur dioxide. The corresponding chemical equation is:
2 PbO(s) + PbS(s) ⇒ 3 Pb(s) + SO₂(g)
We can get the overall reaction by adding both steps and canceling what is repeated on both sides.
2 PbS(s) + 1.5 O₂(g) + 2 PbO(s) ⇒ PbO(s) + 2 SO₂(g) + 3 Pb(s)
2 PbS(s) + 1.5 O₂(g) + PbO(s) ⇒ 2 SO₂(g) + 3 Pb(s)
Question 39 (1 point)
What is the volume (in L) of 4.20 grams of CO2 gas at STP? (
molar masses are,
Carbon = 12.01 g/mol, and oxygen - 16.00 g/mol)
Your Answer:
Answer:
volume = 2128L
Explanation:
volume at stp = 22.4dm³ =22400L
CO2 = 12 + 2(16) = 44
4.20/44 = volume/22400L
0.095 = volume/22400L
volume = 0.095 x 22400
volume = 2128L
NH4NO2(s)→N2(g)+H2O(l) ---------------- Express your answer as a chemical equation. Identify all of the phases in your answer.
Answer:
The balanced equation is :
NH4NO2(solid) = N2(gas) + 2 H2O(liquid)
Explanation:
A balanced chemical equation is an equation that has an equal number of atoms and charges on both sides of the equation. The given equation in question is imbalanced as the number of atoms not equal.
In this reaction, solid ammonium nitrite breaks into nitrogen gas and water, reaction known as decomposition.
The correct and balanced equation as follows :
NH4NO2(s) = N2(g) + 2 H2O(l)
Five mol of calcium carbide are combined with 10 mol of water in a closed, rigid, high-pressure vessel of 1800 cm3 internal empty volume. Acetylene gas is produced by the reaction:
Answer:
CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂
Explanation:
In order to find out the reaction, we must know the reactants.
For this situation, we make acetylene gas from carbide calcium CaC₂ and H₂O (water); therefore the reactants are:
- CaC₂ and H₂O
Acetylene is one of the products made → C₂H₂
So the reaction can be formed as this: CaC₂ + H₂O → C₂H₂
We missed the calcium, and this reaction also makes, Calcium Hydroxide, so the complete equation must be:
CaC₂ + H₂O → C₂H₂ + Ca(OH)₂
This is unbalanced, because we have 1 O in left side and 2 in right side so we add 2 in water so now, we get the complete reaction:
1 mol of calcium carbide reacts to 2 mol of water in order to produce 1 mol of acetylene and 1 mol of calcium hydroxide.
PLEASE ANSWER AS SOON AS POSSIBLE REALLY WOULD APPRECIATE IT
Answer:
The answer is option D.
Hope this helps you
How much MnO2(s) should be added to excess HCl(aq) to obtain 195 mL Cl2(g) at 25 °C and 715 Torr g
THIS IS THE COMPLETE QUESTION
Chlorine can be prepared in the laboratory by the reaction of manganese dioxide with hydrochloric acid, HCl(aq), as described by the chemical equation.
How much MnO2(s) should be added to excess HCl(aq) to obtain 185 mL of Cl2(g) at 25 °C and 715 Torr?
Answer:
0.62901mol of MnO2(s) should be added
Explanation:
Given:
P = 715/760 = 0.94078atm
v=195ml=0.195l
n = ? moles have to find
R = 0.0821 L atm/K/mole
T = 25 + 273 = 298 K
Then we will make use of below formula
PV = nRT
Insert the values
0.94078*0.195=n 0.0821*298
24.466n=0.1740443
n=0.174/24.466
n=0.007235 nb of moles of cl2
as 1 mole of Cl2 were obtained from 1 mole of MnO2
so 0.007235 of chlorine must have come from
0.007235 moles of MnO2
1 mole of MnO2 = 86.94 g/mole
so 0.007235 moles of MnO2== 86.94* 0.007235
=0.62901
How much energy in joules will be required to raise the temperature of 50.0 g of water from 20 degrees C to 60 degree C
Answer: 8368 Joules
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]Q=m\times c\times \Delta T[/tex]
Q = Heat absorbed or released =?
c = specific heat capacity of water = [tex]4.184J/g^0C[/tex]
Initial temperature of water = [tex]T_i[/tex] = [tex]20^0C[/tex]
Final temperature of water = [tex]T_f[/tex] = [tex]60^0C[/tex]
Change in temperature ,[tex]\Delta T=T_f-T_i=(60-20)^0C=40^0C[/tex]
Putting in the values, we get:
[tex]Q=50.0g\times 4.184J/g^0C\times 40^0C=8368J[/tex]
Thus energy in Joules required is 8368.
4Ga + 3S2 ⇒ 2Ga2S3
How many grams of Gallium Sulfide would form if 20.5 moles of Gallium burned?
Answer:
2415.9g (corrected to 1 d.p.)
Explanation:
(Take the atomic mass of Ga=69.7 and S=32.1)
Assuming Ga is the limiting reagent (because the question did not mention the amount of sulphur burnt),
From the balanced equation, the mole ratio of Ga:Ga2S3 = 4: 2 = 2: 1, which means, every 2 moles of Ga burnt, 1 mole of Ga2S3 is produced.
Using this ratio, let y be the no. of moles of Ga2S3 produced,
[tex]\frac{2}{1} =\frac{20.5}{y}[/tex]
y = 20.5 / 2
= 10.25 mol
Since mass = no. of moles x molar mass,
the mass of Ga2S3 produced = 10.25 x (69.7x2 + 32.1x3)
= 2415.9g (corrected to 1 d.p.)
what is the best course of action if solid material remains in the flask after the heating step of recrystallization
Answer:
filter the hot mixture.
Explanation:
Solid is stayed undissolved since the arrangement is gotten super saturated. On the off chance that solid molecule is available recrysallization won't happen in this way we need expel the solid molecule by filtarion in hot condition itself . Subsequently, arrangement become totally homogenous and recrysallization item will shaped by moderate cooling
➔ Which compound has both ionic and covalent bonds? A. Ammonium chloride B. Carbon dioxide C. Ethyl ethanoate D. Sodium chloride
Answer:
Choice A. Ammonium chloride.
Explanation:
Consider the bonds in each of the four compounds.
Ammonium chlorideAmmonium chloride [tex]\rm NH_4Cl[/tex] is an ionic compound. Each
The [tex]\rm {NH_4}^{+}[/tex] and [tex]\rm Cl^{-}[/tex] ions in [tex]\rm NH_4Cl[/tex] are connected with ionic bonds.
What make [tex]\rm NH_4Cl[/tex] special is that its cation [tex]\rm {NH_4}^{+}[/tex] is polyatomic. In other words, each [tex]\rm {NH_4}^{+}[/tex] ion contains more than one atoms. These atoms (one [tex]\rm N[/tex] atom and four [tex]\rm H[/tex] atoms) are connected with covalent bonds. Therefore, [tex]\rm NH_4Cl[/tex] has both ionic and covalent bonds.
Carbon dioxideCarbon dioxide [tex]\rm CO_2[/tex] is a covalent compound. Each [tex]\rm CO_2[/tex] molecule contains two [tex]\rm C=O[/tex] double bonds in total. [tex]\rm CO_2[/tex] molecules have no ionic bond.
Ethyl ethanoateThe name "ethyl ethanoate" might sound like the name of a salt (think about sodium ethanoate.) However, in reality, ethyl ethanoate [tex]\rm CH_3COOCH_2CH3[/tex] is an ester. The "ethyl" here refers to the [tex]\rm -OCH_2CH3[/tex] part, originating from ethanol. On the other hand, "ethanoate" refers to the [tex]\rm CH_3C(O)-[/tex] part, which can be obtained from ethanoic acid.
These two parts are connected with a covalent [tex]\rm C-O[/tex] single bond. (The [tex]\rm C[/tex] in ethanoic acid is connected to the [tex]\rm O[/tex] in ethanol.) As a result, there's no ionic bond in ethyl ethanoate, either.
Sodium chlorideSodium chloride [tex]\rm NaCl[/tex] is an ionic compound. Both the [tex]\rm Na^{+}[/tex] ion and the [tex]\rm Cl^{-}[/tex] are monoatomic. While the [tex]\rm Na^{+}[/tex] and [tex]\rm Cl^{-}[/tex] in sodium chloride are connected with ionic bonds, neither [tex]\rm Na^{+}[/tex] nor [tex]\rm Cl^{-}[/tex] contains covalent bond.