Answer:
790 years
Explanation:
Given that;
0.693/t1/2 = 2.303/t log [A]o/[A]
So;
t1/2 =half life of carbon-14
t= age of the sample
[A]o= activity of the living sampoke
[A] = activity at time t
0.693/5.73 ×10^3 = 2.303/t log 85/77
1.21 × 10^-4 = 2.303/t log 1.1
1.21 × 10^-4 = 0.0953/t
t= 0.0953/1.21 × 10^-4
t= 790 years (to 2sf)
Which of the following is most likely to happen when a sound wave reflects
off a hard surface? (Assume that neither the source of the sound nor the hard
surface is moving.)
A. A change in speed
B. An echo
C. A change in pitch
D. A beat frequency
В
an echo is caused by the fact that waves can be reflected by solid surfaces, this is due to the dynamic pattern of rarefactions and air seals near the reflecting surface
The idea that the behavior of the states of matter is determined by the kinetic energy and movement of their particles is called _____…
A. Sublimation Theory
B. Kinetic Movement Theory
C. Kinetic Molecular Theory
D. Van der Waals Theory
Answer:
C . Kinetic Molecular Theory
Identify the true statements regarding hydrogen bonding. Select all that apply. Group of answer choices Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom.
Answer:
True
Explanation:
Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative element such as N, O, or F.
Hydrogen bonding affects several physical properties of molecules in which it occur. For example, the high boiling point of water is caused by intermolecular hydrogen bonding irrespective of the low relative molecular mass of water.
The statement stating the presence of hydrogen bonding between the hydrogen and N, O, and F has been true.
Hydrogen bonding has resulted when the electrostatic interaction has been found in the atoms that have been more electronegative than the Hydrogen atoms.
The electrostatic force helps in attracting the atoms towards the hydrogen and thereby the hydrogen bonding takes place. It has been a weak force present in the molecules. The hydrogen bonding can be easily breakable.
For more information about hydrogen bonding, refer to the link:
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The decomposition of ammonia is: 2 NH3(g) ⇌ N2(g) + 3 H2(g). If Kp is 1.5 × 103 at 400°C, what is the partial pressure of ammonia at equilibrium when N2 is 0.20 atm and H2 is 0.15 atm?
Answer:
"[tex]6.7\times 10^{-4} \ atm[/tex]" is the right answer.
Explanation:
Given:
Partial pressure of [tex]N_2[/tex],
= 0.20 atm
Partial pressure of [tex]H_2[/tex],
= 0.15 atm
[tex]K_p = 1.5\times 10^3[/tex] at [tex]400^{\circ} C[/tex]
As we know,
⇒ [tex]K_p = \frac{pN_2\times pH_2^3}{pNH_3^2}[/tex]
By putting the values, we get
[tex]1.5\times 10^3=\frac{0.20\times (0.15)^3}{pNH_3^2}[/tex]
[tex]pNH_3^2 = \frac{0.000675}{1.5\times 10^3}[/tex]
[tex]=6.7\times 10^{-4} \ atm[/tex]
What particules make up the nucleus
Answer:
nucleus is a collection of particles called protons,which are positively charged..and neutrons which are electrically neutral..electrons which are negatively charged..and neutrons are in turn made up of particles called quarks ..
Explanation:
hope this helps u ...
Answer:
The Nucleus is made up of protons and neutrons.
Write the balanced equation for the hydration of CuSO4CuSO4. Indicate the physical states using the abbreviations (ss), (ll), or (gg) for solid, liquid, or gas, respectively. Use (aqaq) to indicate the aqueous phase. Indicate appropriate charges on negative and positive ions if they are formed.
Answer:
CuSO4(s) + 5H2O(l) ----> CuSO4.5H2O(s)
Explanation:
Hydration is the process by which anhydrous CuSO4 acquires molecules of water of crystalization to form the pentahydrate.
The water of crystalization becomes attached go the crystals of the CuSO4 to form the hydrated salt.
Beginning with solid anhydrous CuSO4 we have;
CuSO4(s) + 5H2O(l) ----> CuSO4.5H2O(s)
CH3CH2OH
______ions
in an aqueous solution.
А
forms
B
does not form
Answer:
When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). ... Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.
Explanation:
Ethanol is an organic compound with an alcoholic functional group and is nonelectrolytes. Ethanol (CH₃CH₂OH) does not form ions in an aqueous solution. Thus, option B is correct.
What are nonelectrolytes?Nonelectrolytes are substances that do not dissociate readily to yield ions and also are poor conductors of electricity and heat due to a lack of charged ions.
Ethanol is a nonelectrolyte that does not show conductivity and can be dissolved in water without producing ions. They cannot forms ions upon dissociation as covalent bonds are present.
Instead of ions that have covalent compounds that lack the ability to transfer the electron to conduct the electrical charge. Glucose, ethanol, etc. are some examples of a nonelectrolyte.
Therefore, option B. ethanol does not form ions is the correct blank.
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A mixture of argon and neon gases at a total pressure of 874 mm Hg contains argon at a partial pressure of 662 mm Hg. If the gas
mixture contains 12.0 grams of argon, how many grams of neon are present?
Answer:
6.684g
Explanation:
Here, we can use the mole ratio of the gases to calculate.
We know that the mole ratio of the gases equate to their number of moles.
Firstly, we calculate the number of moles of the oxygen gas. The number of moles of the oxygen gas is equal to the mass of the oxygen gas divided by the molar mass of the oxygen gas. The molar mass of the oxygen gas is 32g/mol
Thus, the number of moles produced is 5.98/32 = 0.186875
Where do we move from here?
We know that if we place the partial pressure of oxygen over the total pressure, this would be equal to the number of moles of oxygen divided by the total number of moles. Now let’s do this.
449/851 = 0.186875/n
n =(0.186875 * 851)/449
n = 0.3542
Now we do the same for argon to get the number of moles of argon.
Firstly, we use dalton’s partial pressure law to get the partial pressure of argon. In the simplest form, the partial pressure of argon is the total pressure minus the partial pressure of oxygen.
P = 851 - 449 = 402 mmHg
We now use the mole ratio relation.
402/851 = n/0.3542
n = (402 * 0.3542) / 851
n = 0.1673
Since we now know the number of moles of argon, we can use this multiplied by the atomic mass of argon to get the mass.
The atomic mass of argon is 39.948 amu
The mass is thus 39.948 * 0.1673 = 6.684g
What minimum mass of HCl in grams would you need to dissolve a 2.2 g iron bar on a
padlock?
2.8 g is the minimum mass of HCl in grams that would you need to dissolve a 2.2 g iron bar on a padlock.
What is dissolution?When a solute is dissolved in a solvent, a solution is created. Dissolution is the process through which solutes, or dissolved parts, combine to form a solution inside a solvent. In this procedure, the gas, liquid, or solid dissolves inside the original solvent and forms a solution.
In some polymer applications, dissolution is also an issue since it results in swelling, a loss of strength and stiffness, and a change in volume. Whether a chemical process is man-made or natural, dissolution is crucial. Catalysts are tested using dissolution. 2.8 g is the minimum mass of HCl in grams that would you need to dissolve a 2.2 g iron bar on a padlock.
Therefore, 2.8 g is the minimum mass of HCl in grams that would you need to dissolve a 2.2 g iron bar on a padlock.
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Compounds such as butane and isobutane that have the same molecular formula but differ in the order in which the atoms are connected are called ____________
a. trans isomers
b. cis isomers
c. conventional isomers
d. constitutional isomers
Answer:
One compound, called n-butane, where the prefix n- represents normal, has its four carbon atoms bonded in a continuous chain. The other, called isobutane, has a branched chain. Different compounds that have the same molecular formula are called isomers.
Answer:
d. constitutional isomers
Explanation:
i hope it will help
Can someone teach me step by step how finding the oxidation number in this problem:
Fe in Fe(CIO2)3
Answer:
+3
Explanation:
u see sum of oxidation number in all situations have to be 0
ClO2 =-1
so Fe is +3
please see attachment
Answer:
I'll see it
Explanation:
What is the balanced equation for the reaction of lithium metal with fluorine gas? Li ( s ) + F ( g ) → LiF ( s ) Li ( s ) + F 2 ( g ) → LiF ( s ) 2 Li ( s ) + F 2 ( g ) → 2 LiF ( s ) Li ( s ) + F 2 ( g ) → LiF
Answer:
2Li(s) + F2(g)→2LiF(s)
Explanation:
What is the biggest cause of change in Earth's systems?
A. Heat
B. Motion
C. Friction
D. Plate tectonics
Answer:
heat
Explanation:
because it's the cause of change
Answer:
heat
Explanation:
because it is a natural factor that causes the change in Earth's system
crassify the given quantities into scalar quantity and vetor quantity
Answer:
where is the quantities?
Consider the reaction: A(aq) + 2B (aq) === C (aq). Initially 1.00 mol A and 1.80 mol B
were placed in a 5.00-liter container. The mole of B at equilibrium was determined to
be 1.00 mol. Calculate K value.
0.060
5.1
25
17
Ugh
Answer:
17
Explanation:
Step 1: Calculate the needed concentrations
[A]i = 1.00 mol/5.00 L = 0.200 M
[B]i = 1.80 mol/5.00 L = 0.360 M
[B]e = 1.00 mol/5.00 L = 0.200 M
Step 2: Make an ICE chart
A(aq) + 2 B(aq) ⇄ C(aq)
I 0.200 0.360 0
C -x -2x +x
E 0.200-x 0.360-2x x
Then,
[B]e = 0.360-2x = 0.200
x = 0.0800
The concentrations at equilibrium are:
[A]e = 0.200-0.0800 = 0.120 M
[B]e = 0.200 M
[C]e = 0.0800 M
Step 3: Calculate the concentration equilibrium constant (K)
K = [C] / [A] × [B]²
K = 0.0800 / 0.120 × 0.200² = 16.6 ≈ 17
Decide which of the following statements are true and which are false.
True False: Real gas molecules behave most ideally at low temperature and high pressure.
True False: Ideal gas molecules have small volumes and exert weak attractive forces on one another.
True False: At constant temperature, the heavier the gas molecules, the smaller the average velocity.
True False: In order for two separate 1.0 L samples of O2(g) and H2(g) to have the same average velocity, the O2(g) sample must be at a lower temperature than the H
2(g) sample.
True False: At constant temperature, the heavier the gas molecules, the larger the average kinetic energy.
True False: As temperature decreases, the average kinetic energy of a sample of gas molecules decreases.
Answer:
False
True
True
False
False
True
Explanation:
Ideal behavior of gases is observed at high temperature and low pressure when the gas molecules are isolated from each other.
According to the kinetic theory of gases, gases occupy negligible volume and do not exert significant attractive forces on each other.
The average velocity of gases at constant temperature depends on molecular mass. Heavier molecules possess smaller average velocity than lighter molecules at constant temperature.
At constant temperature, molecules of different gases have the same average kinetic energy but different average velocities since they have different molecular masses. So, the average kinetic energy of gas molecules only depends on temperature.
Hydrocarbons do not dissolve in concentrated sulfuric acid, but methyl benzoate does. Explain this difference and write an equation showing the ions that are produced.
Answer:
See explanation
Explanation:
For a substance to dissolve in another, there must be some sort of interaction between the substances.
Recall that like dissolves like. That is, polar substances dissolve polar substances and non polar substances dissolve nonpolar substances.
Hydrocarbons are nonpolar hence they do not dissolve in polar sulphuric acid. Methyl benzoate is polar hence it dissolve in polar sulphuric acid.
The equation showing the ions is depicted in the image attached to this answer.
describe briefly the laboratory preparation of methane gas
Answer:
In the laboratory, methane is formed by heating sodium ethanoate with a mixture of sodium hydroxide and calcium oxide, called soda lime, on heating in the presence of a catalyst, calcium oxide, the -COONa group from sodium ethanoate is replaced by the hydrogen atom from sodium hydroxide, forming methane and sodium
Explanation:
Calculate the molarity of the following solution.
45.7 g C10H12 in 5230 mL of solution
unit:
Answer:
Molarity = Moles of solute/Volume of solution(in Litres)
Solute = C10H12
moles of solute = Mass/Molar Mass
Molar Mass of C10H12 = 10(12) + 12(1)
= 132gmol-¹
Mole = 45.7/132 = 0.346mol
Molarity = 0.346/5.23
=0.066M
Select all of the statements that are true about a buffer solution. A buffer solution always changes color when the pH changes. A buffer solution reacts with basic solutions. A buffer solution has a pH of 7. A buffer solution resists small changes in pH. A buffer solution reacts with acidic solutions. At what point on the titration curve for a weak acid is the solution a buffer
Answer: A buffer solution reacts with basic solutions.
A buffer solution resists small changes in pH.
A buffer solution reacts with acidic solutions.
Explanation:
A buffer solution simply refers to an aqueous solution that consist of a mixture of a weak acid and the conjugate. From the options given, the ones application to a buffer solution include:
• A buffer solution reacts with basic solutions.
• A buffer solution resists small changes in pH.
• A buffer solution reacts with acidic solutions.
work 10
HOMEWORK ASSIGNMENTS Content
Detai
Question 1
6.25 Points
р А.
71
Calculate AE of a gas for a process in which the gas evolves 24 J of heat and has 9 of work done on it.
A
✓
A -33)
B +33)
Gradin
-220)
D) +15)
E -15)
Question 2
6.25 Points
Answer
A
Explanation:
due to high specific heat capacity it loses heat and has low temperature
If a buffer is composed of 23.34 mL of 0.147 M acetic acid and 33.66 mL of 0.185 M sodium acetate, how many mL of 0.100 M NaOH can be added before the buffer capacity is reached
Answer:
25.5mL of 0.100M NaOH are needed to reach buffer capacity.
Explanation:
The buffer capacity is reached when the ratio between moles of conjugate base (Sodium acetate) and moles of weak acid (Acetic acid) is 10:
Moles sodium acetate / Moles Acetic acid = 10
The reaction of acetic acid, HA, with NaOH, to produce sodium acetate, NaA is:
HA + NaOH → H2O + NaA
That means the moles of NaOH added = Moles of HA that are being subtracted and moles of NaA that are been produced.
The initial moles of each species is:
Acetic acid:
23.34mL = 0.02334L * (0.147mol / L) = 0.00343 moles Acetic Acid
Sodium Acetate:
33.66mL = 0.03366L * (0.185mol / L) = 0.00623 moles Sodium Acetate
We can write the moles of each species when NaOH is added as:
Moles sodium acetate / Moles Acetic acid = 10
0.00623 moles + X / 0.00343 moles - X = 10
Where X are moles of NaOH added
Solving for X:
0.00623 moles + X = 0.0343 moles - 10X
11X = 0.0281
X = 0.00255 moles of NaOH are needed
In Liters:
0.0255mol NaOH * (1L / 0.100mol) = 0.0255L of 0.100M NaOH are needed =
25.5mL of 0.100M NaOH are needed to reach buffer capacity
A Single Orbital With Two Lobes At 90°In A Single Plane And A Node In The Center Would Likely Be Found Where?
a.4s
b.4p
c.4d
d. it would not be found in any of these
e.4f
Is pre ap chemistry hard in high school?
If you don't practice enough it's obviously going to be hard but if you practice enough it's going to be a piece of cake so don't think if it's going to be hard or not just think it's going to be worth the try at the very end
draw all the possible isomers of octane
Answer:
helps
Explanation:
What is a litmus solution? How is it obtained?
During the reaction of 2-methyl-2-butanol with the nucleophile-solvent mixture two layers are formed after shaking the reaction for 5 minutes. After removing the aqueous layer with a Pasteur pipette the organic layer is diluted with 1 mL dichloromethane. The organic phase is washed with 1 mL water. Two layers are obtained.
a. Top layer is Aqueous (H20/ H2SO4/NH4CI)
b. Top layer is Organic (CH2Cl2 and product)
c. Bottom layer is Organic (CH2Cl and product)
d. Top layer is Aqueous (H20)
Answer:
Top layer is Organic (CH2Cl2 and product)
Explanation:
In a solvent mixture, there are usually two phases, the organic phase and the aqueous phase.
It is usual that the organic phase is almost always less dense than the aqueous phase hence the organic phase tend to remain on top of the aqueous phase.
Hence, the top layer is expected to be the organic CH2Cl2 and product.
11. An isotope Q has 18 neutrons a mass number of 34. (a) (i) What is an isotope? An isotope is one of two or C (b) Write its electron arrangement. Mass number=34 Number of neutrons=18 Number of Protons = 34-15-16 (c) To which period and group does Q belong? Protors - Electons - Atomic number Period - Group (d) How does Q form its ion?
An isotope is an element with the same atomic number but different mass number due to differences in number of neutrons.
electron configuration is 2,8,6.
Belongs to group 6 and period group 3.
It forms an ion by accepting 2 electrons
Calculate the heat change in calories for melting of 0.30 kg of water at 0*C. The
heat of fusion for water is 80 cal/g. The heat of vaporization of water is 540 cal/g.
The specific heat capacity of water is 1.00 cal/g*C.
Answer: 24 kcal
Explanation:
Given
Mass of water [tex]m=0.3\ kg[/tex]
Temperature of water [tex]T_1=0^{\circ}[/tex]
Heat of fusion [tex]L_f=80\ cal/g[/tex]
Heat of vaporization [tex]L_v=540\ cal/g[/tex]
Specific heat of water [tex]c=1\ cal/g.^{\circ}C[/tex]
Heat require to melt the ice is
[tex]\Rightarrow Q=mL_f\\\Rightarrow Q=0.3\times 1000\times 80\\\Rightarrow Q=24000\ cal\ or\ 24\ kcal[/tex]
Thus, 24 kcal of heat is required to melt 0.3 kg of ice.
