A. 0.038 g.
Explanation:
The decay of carbon-14 is a first order reaction.
The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5730 year) = 1.21 x 10⁻⁴ year⁻¹.
The integration law of a first order reaction is:
kt = ln [Ao]/[A]
k is the rate constant = 1.21 x 10⁻⁴ year⁻¹.
t is the time = 17,190 years.
[Ao] is the initial concentration of carbon-14 = 0.300 g.
[A] is the remaining concentration of carbon-14 = ??? g.
∵ kt = ln [Ao]/[A]
∴ (1.21 x 10⁻⁴ year⁻¹)(17,190 years) = ln (0.300 g)/[A]
2.08 = ln (0.300 g)/[A]
Taking exponential for both sides:
8.0 = (0.300 g)/[A]
∴ [A] = 0.0375 g ≅ 0.038 g
A 240g hydrated sodium sulphide contains 162g of water of crystallisation. What is the correct molecular formula for this compound?
What is the answer and working
Answer:
Explanation:
First of all, 1 mol of Sodium Sulphide has molecular mass of
S = 32
Na2 = 2*23 = 46
The formula of NaS is actually Na2S. It's molecular mass = 78
How many grams of Na2S are present
Grams present = 240 - 162 = 78 which is exactly 1 mol.
The remainder is water.
The molecular mass of water = 2 + 16 = 18
162 grams of water = 162/18 = 9 mols of water.
So the correct formula is Na2S*9H20
For the metal Mg 109.5g solution HCl 10%. a) Case of metal b) Its properties
Answer:
Explanation:
mg +2hcl=mgcl2 +h2
mhcl=10.95g
nhcl==0.3
nmg=1/2nhcl=0.15
mMg=3.6g
m mgcl2=14.25
Is the following change an oxidation or reduction?
manganese (IV) oxide to manganese (III) oxide.
Answer:
12113
Explanation:
step by step:no
What is the molecular geometry of a molecule made of two atoms that share one pair of electrons and have no lone electrons pairs?
trigonal pyramidal
linear
trigonal planar
bent
Answer:
linear
Explanation:
Actually I consulted various sources too and that was the most sought answer,I just decided to answer you before studying it too
Realiza los cálculos para determinar la cantidad de KOH 90%, que se necesita para preparar 100 ml de solución 1N.
Answer:
6.23 KOH 90% son necesarios
Explanation:
Una solución 1N de KOH requiere 1equivalente (En KOH, 1eq = 1mol) por cada litro de solución.
Para responder esta pregunta se requiere hallar los equivalentes = Moles de KOH para preparar 100mL = 0.100L de una solución 1N. Haciendo uso de la masa molar de KOH y del porcentaje de pureza del KOH se pueden calcular los gramos requeridos para preparar la solución así:
Equivalentes KOH:
0.100L * (1eq / L) = 0.100eq = 0.100moles
Gramos KOH -Masa molar: 56.1056g/mol-:
0.100moles * (56.1056g/mol) = 5.61 KOH se requieren
KOH 90%:
5.61g KOH * (100g KOH 90% / 90g KOH) =
6.23 KOH 90% son necesariosWhat is valence of helium
What is the solubility of salt at 60°C if 2 gm of the salt is left behind when 7 gm of its saturated solution at that temperature dried?
a) 20
b) 40
c) 60
d) 80
40
Explanation:
because its Saturated
How many grams of solute is there in 250 mL of a 0.10M CaCl2 solution ?
Answer:
2.775 g
Explanation:
Given that;
Number of moles = concentration × volume
Concentration = 0.10M
Volume =250 mL
Number of moles = 250/1000 × 0.10
Number of moles = 0.025 moles
Also;
Number of moles = mass/molar mass
Molar mass of CaCl2= 111 g/mol
Mass = Number of moles × molar mass
Mass = 0.025 moles × 111 g/mol
Mass= 2.775 g
A student is asked to convert measurements from meters to millimeters and from millimeters to meters. His answers are
shown in bold in the choices shown below. On which choite did he make a mistake?
9070 mm = 90.7 m
652,222 mm= 652.222 m
37,500 mm = 37.5 m
1.02 x 106 mm = 1020 m
Answer:
The first one
Explanation:
9070 mm = 90.7 m
9070mm is actually equal to 9.07m
What is the standard reduction potential, E, for the half-reaction Al3+ (aq)
3e- -> Al(s)?
Answer:
E° = -1.66 V
Explanation:
The standard reduction potential is also known as the standard electrode potentials and it tries to find the probability that an element will be reduced or undergo reduction.
From activation series online showing the standard reduction potentials for half cells, the standard reduction potential of Al3+ (aq) + 3e- -> Al(s) is;
E° = -1.66 V
(Q008) Two physical properties of minerals both result in smooth, flat surfaces with specific angles between them. The first property is externally visible and is the result of how the mineral forms; the second is inherently internal and is the result of breaking a sample of the mineral. These properties are called
Answer: Crystal habit and cleavage.
Explanation:
When two physical properties of minerals both bring about smooth, flat surfaces that has specific angles between them.such that the first property is externally visible and is the result of how the mineral forms while the second property is internal and is the result of breaking a sample of the mineral, it should be noted that the properties are refered to as the crystal habit and cleavage.
It should be noted that the cleavage refers to the tendency of crystalline materials to be able to split along the structural planes.
Which statement is true?
A. In an exothermic reaction, the energy of the products is the same as the energy of the reactants.
B. In an endothermic reaction, the energy of the products is the same as the energy of the reactants.
C. In an endothermic reaction, the energy of the products is greater than the energy of the reactants.
D. In an exothermic reaction, the energy of the products is greater than the energy of the reactants.
Exothermic reaction is where there is release of energy during a reaction
The enthalpy of exothermic reaction is negative
The relation between energy of products, reactants and enthalpy of reaction is
Enthalpy of reaction = sum of enthalpy of formation of products - sum of enthalpy of formation of reactants .
As enthalpy of reaction is negative, it means the enthalpy of products is less than the enthalpy of reactants so answer is :
In an exothermic reaction the energy of the product is less than the energy of the reactants.
C.
An endothermic reaction is a reaction that absorbs heat from the surroundings. That means that the energy of the system must increase. Therefore, the answer must be C as the products should have higher energy than the reactants.
As a person BAC level increase it becomes difficult for them to judge their vehicle distances and speed
Answer:
TRUE
Explanation:
The blood alcohol content is also known as the blood alcohol level or the blood alcohol concentration. It is defined as the measurement of the alcohol intoxication in the body and is used for the legal or the medical purposes.
When the BAC increases in the person's body, the person started to loose clear vision, loss of short term memory, poor muscle coordination, impaired perception and face difficulty in concentrating. Thus it becomes very difficult for a person to drive a car or ride a bike whose BAC has increased.
The driver cannot properly judge the distances between the vehicle and the speed of the vehicle.
Hence the answer is TRUE.
Atom A and Atom B have the same number of protons and neutrons, but they do not have the same number of electrons. ASAP
Answer:
They will be considered ions of the same element.
Explanation:
Ions form from elements when they gain or loss an electron, causing the number of protons (positively charged) to be unequal to the number of electrons (negatively charged), resulting in a net charge.
If there are more electrons than protons (from an element gaining 1 or more electrons), the ion is negatively charged and is called an anion.
If there are more protons than electrons (via the loss of electrons), the ion is positively charged and is called a cation.
what volume of 2.0 m hcl contains 0.50 mol hcl?
Answer:
the volume of the acid is 250 mL.
Explanation:
Given;
number of moles of the Hcl acid, n = 0.5 mol
concentration of the acid, C = 2.0 M = 2 mol/L
let the volume of the acid = V
The volume of the acid is calculated by applying the following equation;
n = CV
V = n/C
[tex]V= \frac{0.5 \ mol}{2 \ mol/L}[/tex]
V = 0.25 L
V = 250 mL
Therefore, the volume of the acid is 250 mL.
C4H9OH have several isomers. Draw structure and IUPAC names of its three isomers.
Answer:
.
Explanation:
Each orbital can contain no more than 2 electrons. This is:
O A. Conservation of energy
OB. The Pauli exclusion principle
C. None of these
D. Hund's rule
Answer: B. The Pauli exclusion principle.
Explanation: Founders Educere answer ;)
What volume of O2 is required to completely burn 15cm3 of pentane? Equation - C5H12 + O2 - CO2 + H2O.
Answer:
The volume of [tex]\rm O_2[/tex] required would be [tex]120\; \rm cm^{3}[/tex], assuming that both the pentane and the [tex]\rm O_2\![/tex] in this question are ideal gases and are under the same temperature and pressure.
Explanation:
Balance the equation for the reaction:
[tex]\rm ?\; C_{5}H_{12} + ?\; O_2 \to ?\; CO_{2} + ?\; H_{2}O[/tex].
Start by setting the coefficient of the molecule with the largest number of atoms to [tex]1[/tex].
In the combustion of alkanes (including pentane,) consider setting the coefficient of the alkane to [tex]1\![/tex].
[tex]\rm 1\; C_{5}H_{12} + ?\; O_2 \to ?\; CO_{2} + ?\; H_{2}O[/tex].
Number of carbon atoms among the reactants: [tex]5[/tex].
Number of hydrogen atoms among the products: [tex]12[/tex].
By the conservation of atoms, there would need to be the same number of carbon and hydrogen atoms (along with the oxygen atoms) among the products.
Hence, the coefficient of [tex]\rm CO_2[/tex] would be [tex]5[/tex] while the coefficient of [tex]\rm H_2O[/tex] would be [tex]12 / 2 = 6[/tex].
[tex]\rm 1\; C_{5}H_{12} + ?\; O_2 \to 5\; CO_{2} + 6\; H_{2}O[/tex].
There would be [tex]5 \times 2 + 6 \times 1 = 16[/tex] oxygen atoms among the products. Also by the conservation of atoms, there would be the same number of oxygen atoms among the reactants.
Hence, the coefficient of [tex]\rm O_2[/tex] would be [tex]16 / 2 = 8[/tex].
[tex]\rm 1\; C_{5}H_{12} + 8\; O_2 \to 5\; CO_{2} + 6\; H_{2}O[/tex].
The ratio between the coefficient of [tex]\rm O_2[/tex] and [tex]\rm C_{5}H_{12}[/tex] in the balanced equation is:
[tex]\displaystyle \frac{n({\rm O_2})}{n({\rm C_{5}H_{12}})} = \frac{8}{1} = 8[/tex].
In other words, it would take eight [tex]\rm O_2[/tex] molecules to react with one [tex]\rm C_{5}H_{12}[/tex] molecule.
Assume that both [tex]\rm O_2[/tex] and [tex]\rm C_{5}H_{12}[/tex] are ideal gases. Under the same temperature and pressure, the volume of the two gases would be proportional to the number of molecules in each gas:
[tex]\displaystyle \frac{V({\rm O_2})}{V({\rm C_{5}H_{12}})} = \frac{n({\rm O_2})}{n({\rm C_{5}H_{12}})} = \frac{8}{1} = 8[/tex].
In other words, it would take [tex]8\; \rm cm^{3}[/tex] of [tex]\rm O_2[/tex] to react with [tex]1\; \rm cm^{3}[/tex] of [tex]\rm C_{5}H_{12}[/tex] under these assumptions. It would then take [tex]8 \times 15\; \rm cm^{3} = 120\; \rm cm^{3}[/tex] of [tex]\rm O_2\![/tex] to react with [tex]15\; \rm cm^{3}\![/tex] of [tex]\rm C_{5}H_{12}\![/tex].
I need help getting this done
Answer:
I put the right structures in the pictures for you
from the equation 2PbO + C = 2Pb + CO2, detemine which one is reactant is oxidised and which is reduced.
Answer:
Explanation:
C is oxidised because C up to C+4
PbO is reduced because PbO from Pb2+ down to Pb0
Answer:
lead (Pb) is reduced carbon is oxidized
19. If 23.4 grams of hydrogen gas were produced by the reaction below, how many grams of aluminum chloride were produced? (2 points) 2 Al + 6 HCl yields 2 AlCl3 + 3 H2 516 g AlCl3 774 g AlCl3 1030 g AlCl3 1550 g AlCl3
Answer:
1040
Explanation:
you can use the mole to mole ratios of aluminum chloride and hydrogen gas,you first have to find the number of moles of hydrogen gas..the number of moles of hydrogen gas are 11.7(23.4/2)
2AlCl3+3H2
2 : 3
x :11.7
3x/3=23.4/3
x=7.8g/mol
then find the number of grams of aluminum chloride
m=n×mr
=7.8×133.341
=1040g
I hope this helps and sorry if it's wrong
Which group of elements is generally unreactive? O A. Noble gases O B. Halogens O C. Alkali metals D. Nitrogen family
Answer:
Nobles Gases Are the group of elements which are generally unreactive
I Hope its right if not then Sorry, have a wonderful day :)what is true about solubility
Explanation:
Solubility is defined as a property of solutes by virtue of which they get dissolved in a favorable solvent. The solute can only be dissolved in any suitable solvent up to a limit at a given temperature. This is a characteristic of the the solute-solvent pairing.
calculate molarity, molality and mole fraction of 28 percent aqueous solution of a solute with molar mass 11.5 g per mole and density is 1.25 g per mole
Explanation:
Aight, I'mma give tell ya an easy way for this question. look at this Forumla
M=
[tex] \frac{10ad}{m} [/tex]
a explains the percentage of aqueous solution
d is the density
m is the molar mass
right, let's just hop to it
M=10×28×1.25/11.5====> M=30.43
11. A mixture of magnesium powder and lead (II) Oxide will react vigorously when heated but no reaction occurs when a mixture of magnesium oxide and lead powder are heated, a) Explain the observation. b Which of the two substances, magnesium or lead(IT) Oxide is; i) Oxidized in the reaction? ii) Oxidizing agent? C Which is the most reactive metal Please helpA
Answer:
17
Explanation:
i need points
Define an ideal gas and explain under which conditions you may reasonably approximate a real gas as an ideal gas. Also mention conditions under which it would be inappropriate to approximate a real gas as an ideal gas. (you may need to use a search engineto help you out here)
Answer:
High temperature and low pressure
Explanation:
According to the kinetic molecular theory, gases are composed of small particles called molecules which are in constant motion.
At high temperature and low pressure, gas molecules possess high kinetic energy and move at high velocities hence intermolecular interaction is almost none existent and real gases approach the behavior of ideal gases.
Freezing point depression is:
A. When a substance freezes and then quickly drops in temperature.
B. When a substance drops in temperature until it freezes, then quickly rises in temperature but stays frozen.
C. When a substance does not need to be as cold as normal in order to freeze.
D. When a substance must be colder than normal in order to freeze.
Freezing point depression is when a substance must be colder than normal in order to freeze.
Freezing point is that temperature where a liquid substance becomes a solid i.e. freezes. Freezing point depression is the process whereby the temperature at which a substance freezes is lowered.Freezing point depression often occurs when a solute is added to a solvent. This reduces its freezing point. Since temperature is reduced, in other words, this means that the substance must become colder than normal for it to start freezing.
Hence, freezing point depression is when a substance must be colder than normal in order to freeze.
Learn more at: https://brainly.com/question/2785367
D. When a substance must be colder than normal in order to freeze.
Explanation:
hey love, I just took the quiz on this for founder's education. I hope this helped.
A student measures the volume of a small irregularly- shaped stone. Which apparatus must be used? a. a measuring cylinder containing water and a ruler only. b. a measuring cylinder containing water only. c. an empty measuring cylinder and a ruler only. d. a ruler only.
Answer:
a measuring cylinder containing water only.
Explanation:
If we want to measure the volume of an irregular object. We need a properly calibrated measuring cylinder filled with water of known volume.
The irregular object is now inserted into the measuring cylinder containing water and the change in the volume of water is noted. The volume of the irregular object is now obtained as;
New volume of water - initial volume of water.
Hence, only a measuring cylinder filled with water is required to measure the volume of a small irregularly- shaped stone.
PLZ HELP ME Which of the following lists the levels of body organization in order from most basic to most complex?
A Tissues, organs, body systems, cells
B. Cells, tissues, organs, body systems
C. Cells, organs, body systems, tissues
D. Tissues, cells, organs, body systems
Answer:
It is B
Explanation:
I was able to find my school notes and double-check. I hope you have a nice day!
Which of the following describes metallic character on the periodic table? Question 1 options: A) It increases as you move right to left within a period and down a group on the periodic table. B) It increases as you move left to right within a period and down a group on the periodic table. C) It increases as you move left to right within a period and up a group on the periodic table. D) It increases as you move right to left within a period and up a group on the periodic table.
Answer:
D
Explanation:
Metallic character decreases as you move across a period in the periodic table from left to right. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell. Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.
