Answer:
Chlorine's (Cl) atomic mass if 17.
Explanation:
"Chlorine (atomic number 17) is a yellowish-green toxic gas. About three quarters of all chlorine atoms have 18 neutrons, giving those atoms a mass number of 35. About one quarter of all chlorine atoms have 20 neutrons, giving those atoms a mass number of 37."
How much heat is required to vaporize 15.8 g CH3OH(l) at its boiling point? (∆Hvap = 38.0 kJ/mol) a a. 2.41 kJ b 77.0 kJ c 18.8 kJ d 600. kJ
Answer:
be.77.0kj.
Explanation:
add moles then times
Considering the definition of enthalpy of vaporization, the correct answer is option c. the heat required to vaporize 15.8 g of CH₃OH at its boiling point is 18.8 kJ.
When a material changes phase from solid to liquid, or from liquid to gas, a certain amount of energy is involved in this phase change.
In case of phase change from liquid to gas, this amount of energy is known as enthalpy of vaporization (symbolized as ∆H vap), also known as (latent) heat of vaporization or heat of evaporation.
In other words, the enthalpy of vaporization is the amount of energy required to change a unit of mass (for example, moles or kg) of a substance from phase liquid to phase gas at constant temperature and pressure.
In this case, you know that enthalpy of vaporization is ∆Hvap = 38.0 kJ/mol.
On the other side, you want to vaporize 15.8 g of CH₃OH. Then, being the molar mass of the compound 32 g / mole (that is, the amount of mass contained in one mole), the number of moles to be vaporized is:
[tex]15.8 gramsx\frac{1 mol}{32 grams}= 0.49375 moles[/tex]
Then, the heat required to vaporize 0.49375 moles of CH₃OH at its boiling point is calculated taking into account the enthalpy of vaporization by:
0.49375 moles× 38.0 kJ/mol= 18.76 kJ ≅ 18.8 kJ
Finally, the correct answer is option c. the heat required to vaporize 15.8 g of CH₃OH at its boiling point is 18.8 kJ.
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Answer:
[H₃O⁺] = 0.0507 M
pH = 1.29
Explanation:
23.1 g of HCI (a strong acid) is added to water to make 1250 mL of solution. Calculate [H₃O⁺] and pH of the solution.
Step 1: Given data
Mass of HCl (solute): 23.1 gVolume of solution: 1250 mLStep 2: Calculate the concentration of HCl
We will use the following expression.
[HCl] = mass HCl / molar mass HCl × liters of solution
[HCl] = 2.31 g / 36.46 g/mol × 1.250 L
[HCl] = 0.0507 M
Step 3: Calculate the concentration of H₃O⁺
HCl is a strong acid according to the following equation.
HCl(aq) + H₂O(l) ⇒ H₃O⁺(aq) + Cl⁻(aq)
The molar ratio of HCl to H₃O⁺ is 1:1. Then, [H₃O⁺] = 0.0507 M.
Step 4: Calculate the pH of the solution
We will use the following expression.
pH = -log [H₃O⁺]
pH = -log 0.0507
pH = 1.29
Question 4 of 5
Most paints include a pigment (the color), a binder (the
glue), and a solvent. The binder makes the paint color stick
to the surface being painted.
Which part of the manufacturing process occurs when binders are added to a
paint mixture?
A. Separating
B. Forming
C. Finishing
D. Combining
SUE
Answer:
answer is d Combining
Explanation:
I did the test and got it correct
As a chemical change takes place when binders are added to a paint mixture combining part of the manufacturing process occurs.
What are chemical changes?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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Which is an advantage of using gymnosperms as decorative outdoor plants around homes and businesses?
Most of them do not grow very tall.
Most of them stay green all year.
All of them produce colorful flowers,
All of them have sharp needle-like leaves.
Answer:
i just took the test the correct answer is "most of them stay green all year"
Explanation:
Answer:
its B :)
Explanation:
cuz im mr beast
a single covalent bond is made up of
Answer:
In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond.
Explanation:
(copied from Google)
If 19.2 grams of O2 reacts with iron to form iron oxide how much iron was used in the reaction? use the equation 4Fe + 3O2 — 2Fe2O3 to help
Answer:
44.8g
Explanation:
The reaction equation is given as:
4Fe + 3O₂ → 2Fe₂O₃
Given:
Mass of O₂ = 19.2g
Unknown:
Amount of iron used =?
Solution:
To solve this problem, we adopt the mole concept.
Since we know the mass of O₂;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of O₂ = 2(16) = 32g/mol
Number of moles = [tex]\frac{19.2}{32}[/tex] = 0.6moles
From the balanced reaction equation;
4 moles of Fe will react with 3 moles of O₂
0.6moles of O₂ will react with [tex]\frac{0.6 x 4}{3}[/tex] = 0.8mole of Fe
Mass of Fe = number of moles x molar mass
= 0.8 x 56
= 44.8g
show is a pedigree chart. the chart shows that sally is carrier for red-green color blindness
Answer:
you cant post pictures on brainly answers.... can you?
Explanation:
If we combine the reaction of an acid protonating water and the reaction of its conjugate base deprotonating water, the net reaction after canceling common terms is:______
a. The acid-base reaction between the acid and its conjugate base.
b. The synthesis of a complex between the acid and its conjugate base.
c. The autoionization of water
d. None of the above
Answer:
C
Explanation:
The net reaction after canceling common terms should be considered as the autoionization of water.
What is autoionization of water?Since acids and bases should be react with each other, this shows that water could be react with itself. Here the sound should be stranged. Also, the water molecules should be exchanged the protons to the small extent.
hence, The net reaction after canceling common terms should be considered as the autoionization of water.
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the number of elements in 2CH4
Answer:mnedd kfj
Explanation:
fr rb r
Sonar uses ____________ waves to tell how ____________things are in the water.
would you like to explore outer space? Why or why not? If you could travel to any part of the galaxy at lightning speed would like to see what is truly out in the universe would you do it? Why or why not?
Answer:
Yes!
Explanation:
I think It would be fun!, Going thought space going from planet to planet. once i get back to earth i can make a document about my time in space.
Which of the following most likely causes the rate of a chemical reaction to increase?
Answer:
Adding heat to the reaction or increasing pressure
Explanation:
Increasing temperature or pressure will result in chemical reaction rates to speed up.
q=m(delta)T Calculate the final temperature reached when 324 J of heat is added to a 22.5g iron bar initially at 20.0 degrees C. The specific heat capacity of iron is 0.45 J/g degrees C.
Answer:
T(final) = 52°C
Explanation:
1st, you need to correct your heat flow formula => q = mcΔT.
m = 22.5g
c = 0.45 j/g·°C
ΔT = T(final) - T(initial) = T(final) - 20°C
q = (22.5g)(0.45j/g·°C)((final) - 20°C) = 324j
=> T(final) = [324j/(22.5g)(0.45j/g·°C)] + 20°C = 52°C
can you help me out pleas
Answer:a a atom
Explanation:
Answer:
a. carbon
b. atomic number
c. mass number
d. 6
e. 7
f. 8
pls mark as brainliest
The ion formed by an atom of sulfur when it gains two electrons is called a:
Do not answer cation or anion
Answer:
sulfide ion
Explanation:
however, when non-metalic elements gain electrons to form anions the end of their name is change to "-ide".foe example, a flourin atom gains one electronto become a flouride ion(F`) and sulfur gains two electrons to become a sulfide ion(s^2)
Liquid 1 has a density of 2.0 g/ml, Liquid 2
has a density of 1.5 g/ml, and Liquid 3 has a density of 1.8 g/ml. Which liquidwill make up
the top layer?
Liquid 2 because the lower the density the more it floats and the higher the density the more it sinks. The order from top to bottom is liquid 2, liquid 3, liquid 1
How does the wind pattern during the day compare with the wind pattern at night?
What neutral element will have the electron configuration 1s22s22p63s23p1?
Select one:
a. aluminum
b. boron
c. carbon
d. silicon
Answer:
a. aluminum
Explanation:
Given electronic configuration:
1s² 2s² 2p⁶ 3s² 3p¹
The number of electrons can be determined from adding the powers or superscripts.
Since we are dealing with a neutral element, the number of electrons and protons are the same. So we can determine the atomic number which is the number of protons.
Number of electrons = 2 + 2 + 6 + 2 + 1 = 13
The element with atomic number 13 is aluminum.
The given electronic configuration adds up to 13 which is the atomic number of aluminium.Thus, the correct option is A.
Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable. Aluminium has the given electronic configuration.
Thus, the correct option is A.
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each substance in a solution mixture is visible to the naked eye? True or False
What is the compound NH3
Just enough 0.500 M HCl is added to 30.0 mL of 2.5 M NH3 to reach the equivalence point. The Kb of NH3 = 1.8 X 10-5
Write the balanced equation for this reaction.
What volume of 0.500 M HCl solution was added?
What is the molarity of the salt produced from the neutralization reaction?
What is the pH of the solution at the equivalence point?
a.NH₃+HCl⇒NH₄Cl
b.volume HCl=150 ml
c. pH=4.82
Further explanationReaction
NH₃+HCl⇒NH₄Cl
The equivalence point⇒mol NH₃=HCl
Titration formula :
M₁V₁n₁=M₂V₂n₂(n=acid base valence, NH₃=HCl=1)
mol NH₃
[tex]\tt 2.5\times 30=75~mlmol[/tex]
mol HCl=75 mlmol
Volume HCl :[tex]\tt \dfrac{75}{0.5}=150~ml[/tex]
Volume total :
[tex]\tt 150+30=180~ml[/tex]
molarity of salt(NH₄Cl)mol NH₄Cl=mol NH₃=75 mlmol=0.075 mol
[tex]\tt M=\dfrac{0.075}{0.180}= 0.42[/tex]
pH of solutionDissociation of NH₄Cl at water to find [H₃O⁺]
[tex]\tt NH_4+H_2O\rightarrow NH_3+H_3O^+[/tex]
ICE at equilibrium :
0.41-x x x
Ka(Kw:Kb)= 10⁻¹⁴ : 1.8.10⁻⁵=5.6.10⁻¹⁰
[tex]\tt Ka=\dfrac{NH_3.H_3O}{NH_4}=\dfrac{x^2}{0.41}[/tex]
[H₃O⁺]=x :
[tex]\tt \sqrt{5.6.10^{-10}\times 0.41}=1.515.10^{-5}[/tex]
pH=-log[H₃O⁺]
[tex]\tt pH=5-log~1.515=4.82[/tex]
When elements bond together or when bonds of compounds are broken and form a new substance
A. Fireworks
B. Chemical Reaction
C. Chemical Change
D. Energy
Which fossil fuel is made when plants from swamps are covered, pressed, and heated for millions of years? A Coal B Petroleum C Natural Gas D Nuclear
Answer:
A: COAL
Explanation:
Coal was created hundreds of millions years ago. When prehistoric plant life died and sank to the bottom of the swamp and was covered by layers of sediment.
What is the structure of amylopectin?
Answer:
Not sure if you just wanted the basic structure or full on structure.
Explanation:
Which are the products in the equation CH3SH + 4O2 → CO2 + SO2 +2H2O? Check all that apply. CH3SH O2 CO2 SO2 H2O
To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the products are carbon dioxide, sulfur dioxide and water.
What is Balanced equation?Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.
The other characteristic of balanced equation is that physical state should be written with each compound or molecule on reactant and product side. Physical state should be written in brackets. s means solid, l means liquid, g means gas.
The balanced equation is
CH[tex]_3[/tex]SH + 4O[tex]_2[/tex] → CO[tex]_2[/tex] + SO[tex]_2[/tex] +2H[tex]_2[/tex]O
The products that are formed in the given reaction are carbon dioxide, sulfur dioxide and water.
Therefore, the products are carbon dioxide, sulfur dioxide and water.
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If I start with 0.0350 L of a 12.0 M hydrochloric acid solution, and dilute it with water to a new volume of 1.20 L, what is the new concentration?
Answer:
0.35 M
Explanation:
Using the formula; C1V1 = C2V2
Where;
C1 = concentration of initial solution
C2 = concentration of final solution
V1 = volume of initial solution
V2 = volume of final solution
Based on this question, I start with 0.0350 L of a 12.0 M hydrochloric acid solution, and dilute it with water to a new volume of 1.20 L. This means that:
C1 = 12.0 M, V1 = 0.0350 L, V2 = 1.20 L, C2 = ?
Hence, C1V1 = C2V2
12 × 0.0350 = C2 × 1.20
0.42 = 1.2C2
C2 = 0.42/1.2
C2 = 0.35 M
Identify the true statements about introns.a- they code for polypeptide proteinsb- they have a branch site located 20 to 50 nucleotides upstream of the 3' splice sitec- they end with the nucleotides AG at the 3' endd- they begin with the nucleotides GU at the 5' ende- they tend to be common in bacterial genes
Answer:
The answer is "Option b, c, and d".
Explanation:
In such a gene, Autosomes are also the sequence for code and transposable elements, not the series of encoding. Through the expression of genes, such fragments of its introns are split through protein complexes throughout the translation process. There has been no kenaf fiber in the genomes of prokaryotic cells.
a solution is made by dissolving 25g of nacl in 300g of water. What is the mass percentage
Answer:
0.83 bar
That is
23/300*100
=0.83 bar
Which pair of atoms are isotopes ?
Answer:
If two atoms have different numbers of protons, they are different elements. However, if two atoms have the same number of protons, but different numbers of neutrons we refer to them as isotopes. Two terms we use to identify nuclides (isotopes) are atomic number and mass number.
Explanation:
Your Welcome!
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, in below given ways we can identify isotopes.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
Differing elements exist when two atoms contain different numbers of protons. If two atoms contain the same amount of protons but differing numbers of neutrons, they are referred to be isotopes.
Therefore, in above given ways we can identify isotopes.
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A 25.225 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 75.815 g of water. A 14.842 g aliquot of this solution is then titrated with 0.1068 M HCl . It required 29.99 mL of the HCl solution to reach the methyl red endpoint. Calculate the weight percent NH3 in the aqueous waste
Answer:
1.43 (w/w %)
Explanation:
HCl reacts with NH3 as follows:
HCl + NH3 → NH4+ + Cl-
1 mole of HCl reacts per mole of ammonia.
Mass of NH3 is obtained as follows:
Moles HCl:
0.02999L * (0.1068mol / L) = 3.203x10-3 moles HCl = Moles NH3
Mass NH3 in the aliquot:
3.203x10-3 moles NH3 * (17.031g / mol) = 0.0545g.
Mass of sample + water = 22.225g + 75.815g = 98.04g
Dilution factor: 98.04g / 14.842g = 6.6056
That means mass of NH3 in the sample is:
0.0545g * 6.6056 = 0.36g NH3
Weight percent is:
0.36g NH3 / 25.225g * 100
1.43 (w/w %)