Answer:
The tasks which form the preliminaries to a descriptive investigation are: Making careful objective observations. Asking the relevant scientific questions.
The energy of a photon that has a frequency of 1.821 x 1016 5-1 is blank j?
Answer:
1.207 ××10⁻¹⁷ J
Explanation:
Step 1: Given and data
Frequency of the photon (ν): 1.821 × 10¹⁶ s⁻¹Planck's constant (h): 6.626 × 10⁻³⁴ J.sStep 2: Calculate the energy (E) of the photon
We will use the Planck-Einstein's relation.
E = h × ν
E = (6.626 × 10⁻³⁴ J.s) × ( 1.821 × 10¹⁶ s⁻¹) = 1.207 ××10⁻¹⁷ J
The main product of free radical bromination of methane is
A) ethane
B) chloromethane
C) bromonethane
D) bromine
Answer: C
Explanation:
5pts) Reaction Characterization (1pts) Select the type of reaction Choose... (1pts) Write the balanced equation for the formation of the Grignard reagent from bromobenzene. Include all reagents and products but not solvents.
Answer:
See explanation and image attached
Explanation:
Grignard reagent is any organic compound that is classified as an alkyl or aryl magnesium halide (RMgX).
Grignard reagents are produced when the alkyl halide reacts with magnesium metal in ether and tetrahydrofuran as solvents.
They are good nucleophiles and are involved in the synthetic routes to many important classes of organic compounds.
The formation of Grignard reagent from bromobenzene is shown in the image attached to this answer.
La is element 57 on the periodic table a sample contains 2.82 * 10€25 power atoms of La calculate the amount of LA
Answer:
[tex]n=46.8molLa\\\\m=6.50x10^3gLa[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate both moles and grams of lanthanum by using the Avogadro's number as a relationship of atoms to moles and its atomic mass as a relationship to moles to grams to obtain the following:
[tex]n=2.82x10^{25}atomsLa*\frac{1molLa}{6.022x10^{23}atomsLa}=46.8molLa\\\\m=46.8molLa*\frac{138.9gLa}{1molLa} =6.50x10^3gLa[/tex]
Regards!
What size volumetric flask would you use to create a 1.00M solution using 166.00 g of KI?
Answer:
A 1 liter volumetric flask should be used.
Explanation:
First we convert 166.00 g of KI into moles, using its molar mass:
Molar mass of KI = Molar mass of K + Molar mass of I = 166 g/mol
166.00 g ÷ 166 g/mol = 1 mol KIThen we calculate the required volume, using the definition of molarity:
Molarity = moles / litersLiters = moles / molarity
1 mol / 1.00 M = 1 Lthe intrument that tells both the speed and direction of the wind is the?
Answer:
anemometer
Explanation:
The instrument that is being described is called an anemometer. This is a device that has 4 ladel like objects that allow the wind to hit it, causing it to spin. The force of the spin allows meteorologists to calculate the speed of the wind. On top of this device is usually an arrow which can rotate around the device with the wind and point in the direction that the wind is blowing. Using a N, NE, E, SE, S, SW, W, and NW direction.
Which of the following is true for a nuclear reaction? (5 points)
Select one:
a.Electrons are lost.
b.Electrons are gained.
c.The identity of element changes.
d.The identity of element remains same.
the identity of element remains same
An article about half-lives describes a parent isotope. What is a parent isotope?
A. The isotope that forms from the radioactive decay of a less stable isotope.
B. The isotope that forms from the radioactive decay of a more stable isotope.
C. The isotope that undergoes radioactive decay to form a less stable isotope.
D. The isotope that undergoes radioactive decay to form a more stable isotope.
I think the answer is D.
Answer:
D. The isotope that undergoes radioactive decay to form a more stable isotope.
Explanation:
In radioactivity, isotopes of an unstable atom disintegrates/decays into more stable ones accompanied with the emissions of certain particles e.g alpha, gamma and beta particles.
In this process, the isotope of the atom that undergoes radioactive decay to form a more stable isotope is known as the PARENT ISOTOPE while the more stable isotope that arises from the decay is called the DAUGHTER ISOTOPE.
(238, 92) Uranium → (234,90) Thorium + (4,2) Helium
In the above reaction, Uranium is the parent isotope because it decays into a more stable isotope (Thorium).
Answer:
He's Right
Explanation:
i got it right
What would happen to the Earth's hydrosphere if there were no atmosphere?
PLZZZ HELPPPPPPPPPPPPPPPPPPPPP
Answer:
1 +-0.05cm
Explanation:
because this is more suitable
A certain alkyl halide is reacted with OH- to form an alcohol. The alkyl halide is optically active but the product(s) is/are optically inactive. Which of the following could be the reactant?a) 3-bromo-3-methylhexane.b) 1-chlorobutane.c) 2-bromo-2-methylbutane.d) 3-bromo-2,3,4-trimethypentane.
Answer:
a. 3-brumo - 3-methylhexane
Explanation:
Alkyl Halides can undergo substitution reactions. Nucleophiles are electron rich species and has negative charge while Electrophiles are electron deficient species which carry positive charge. Alkyl halide which have polar carbon atom are electrophiles.
“Conductor, circuit breaker, switch” use the words provided to write the function of fuses.
Answer pls
Answer:
The fuse is a thin wire that is the conductor of electricity is designed to breaks the circuit if there is a fault in an appliance that causes excessive current to flow in a circuit.
The conductor used in the fuse is melt and separated in such cases of excessive current in a circuit and switch the current off.
A circuit breaker is made up of a thin wire that is specially designed to switch that automatically breaks circuit current in the overcurrent condition.
What is the initial pressure of a gas if it’s occupied a volume of 0.375 L but now occupies a volume of 1.25 L at a pressure of 95.5 K PA
Answer:
318 kPa
Explanation:
Step 1: Given data
Initial pressure (P₁): ?Initial volume (V₁): 0.375 LFinal pressure (P₂): 95.5 kPaFinal volume (V₂): 1.25 LStep 2: Calculate the initial pressure of the gas
Assuming constant temperature and ideal behavior, we can calculate the initial pressure of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
P₁ = P₂ × V₂ / V₁
P₁ = 95.5 kPa × 1.25 L / 0.375 L = 318 kPa
Soybeans is used in food production and cooking in 2007 United States produced 3.06 billions bushels of soybeans and 65% of the harvest was used to make soybeans oil
Answer:
1.071
Explanation:
Answer:
Find the percentage of soybeans used for other purposes:
100% − 65% = 35%.
Multiply the result (35%) by the total bushels of soybeans produced:
35
100
=
0.35
.
0.35 × 3.06 billion bushels = 1.071 billion bushels
The amount of soybeans used for other purposes was 1.071 billion bushels.
Explanation:
PLATO
Use the electronic configuration to explain the occurrence of period and groups to the periodic table.
Answer:
H2O
Explanation:
hydrogen has 1 electron
and oxygen has 6 electron which form a water molecule Atom
Calculate the amount of heat needed to melt 89.9 g of solid methanol (CH3OH) and bring it to a temperature of 49.1C.
Answer:
20075.35 J
Explanation:
We'll begin by calculating the number of mole in 89.9 g of CH₃OH. This can be obtained as follow:
Mass of CH₃OH = 89.9 g
Molar mass of CH₃OH = 12 + (3×1) + 16 + 1
= 12 + 3 + 16 + 1
= 32 g/mol
Mole of CH₃OH =?
Mole = mass / molar mass
Mole of CH₃OH = 89.9 / 32
Mole of CH₃OH = 2.81 moles
Next, we shall determine the heat required to melt the solid methanol (CH₃OH). This can be obtained as follow:
Mole of CH₃OH (n) = 2.81 moles
Heat of fusion (Hբ) = 3.17 KJ/mol
Heat required to melt CH₃OH (Q₁) = ?
Q₁ = n × Hբ
Q₁ = 2.81 × 3.17
Q₁ = 8.9077 KJ
Converting to J
Q₁ = 8.9077 × 1000
Q₁ = 8907.7 J
Next, we shall determine the heat required to change the temperature of methanol to 49.1 °C. This can be obtained as follow:
Mass of CH₃OH (M) = 89.9 g
Initial temperature (T₁) = 0 °C
Final temperature (T₂) = 49.1 °C.
Specific heat capacity of CH₃OH (C) = 2.53 J/gºC
Heat required to change the temperature (Q₂) =?
Q₂ = MC(T₂ – T₁)
Q₂ = 89.9 × 2.53 × (49.1 – 0)
Q₂ = 89.9 × 2.53 × 49.1
Q₂ = 11167.65 J
Finally, we shall determine the total heat. This can be obtained as follow:
Heat required to melt CH₃OH (Q₁) = 8907.7 J
Heat required to change the temperature (Q₂) = 11167.65 J
Total heat required (Q) =?
Q = Q₁ + Q₂
Q = 8907.7 + 11167.65
Q = 20075.35 J
Therefore, the total heat required to melt the methanol and bring it to a temperature of 49.1 °C is 20075.35 J
How many joules of heat energy are required to raise the temperature of 100.0 g of aluminum by 120.0°C? The specific heat of aluminum is 0.897 J/g.°C. 2 3
Answer:
10764 J
Explanation:
Remember the equation for specific heat::
q = mcΔT
q = 100 x 0.897 x 120
q = 10764
. ¿Cuantos moles de Fosfato de Bario se producen cuando reaccionan 0.38 mol de Nitrato
de bario? Suponga que el ácido fosfórico está en exceso. Base sus cálculos en la siguiente
ecuación.
Ba(NO3)2(aq) + HAPO.(aq)
Ba,(PO.),(s) + HNO3(aq)
-
Respuesta:
0.13 mol
Explicación:
Paso 1: Escribir la ecuación química balanceada
3 Ba(NO₃)₂ + 2 H₃PO₄ ⇒ Ba₃(PO₄)₂ + 3 H₂O
Paso 2: Establecer la relación molar apropiada
La relación molar de Ba(NO₃)₂ a Ba₃(PO₄)₂ es 3:1.
Paso 3: Calcular cuantos moles de fosfato de bario se producen a partir de 0.38 moles de nitrato de bario
0.38 mol Ba(NO₃)₂ × 1 mol Ba₃(PO₄)₂/3 mol Ba(NO₃)₂ = 0.13 mol Ba₃(PO₄)₂
Select all the correct answers
When two generalizations can be made based on what you know about cycles of matter in a closed system?
New matter is added, and old matter is destroyed.
Matter changes its physical form, allowing it to return to its original state.
The amount of matter within the system remains the same
Matter and energy can cross the boundaries of the system.
The cycle has a well-defined starting and Stopping point
Answer:
A
Explanation:
How many moles are present in a sample if it consists of 5.61x1022 particles? Report your answer to 3 decimal places. Do not include units.
Answer:
The mole is defined as a collection of 6.022 × 1023 particles.
The atomic mass given on a periodic table that is given in grams is the mass of
one mole (6.022 × 1023 particles) of that element
Explanation:
which effect of long-term environmental change is the driving force behind evolution?
Answer:
climate change
Explanation:
climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.
10-Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solvent. What is the molarity of a solution containing 9.478 grams of Rucl, in enough water to make 1.00 L of solution?
Answer:
0.0457 M
Explanation:
Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solution. What is the molarity of a solution containing 9.478 grams of RuCl₃, in enough water to make 1.00 L of solution?
Step 1: Given data
Mass of RuCl₃ (solute): 9.478 gVolume of solution: 1.00 LStep 2: Calculate the moles corresponding to 9.478 g of RuCl₃
The molar mass of RuCl₃ is 207.4 g/mol.
9.478 g × 1 mol/207.4 g = 0.04570 mol
Step 3: Calculate the molarity of the solution
We will use the definition of molarity.
M = moles of solute / liters of solution
M = 0.04570 mol / 1.00 L = 0.0457 M
The acid dissociation constant, Ka, of HNO3 is 4.0 x104. What does the ka
value indicate about this compound?
A. HNO3 is neither an acid nor a base,
B. HNO3 is a strong acid.
C. HNO3 is a weak acid
D. HNO3 is a strong base.
Answer:
i thing its b
Explanation:
The acid dissociation constant (Ka) is a measure of the strength of an acid in solution. In HNO₃ (nitric acid), the given Ka value is 4.0 x 10⁴. It represents the equilibrium constant for the dissociation reaction of an acid in water. Therefore, option B is correct.
The dissociation constant often denoted as Kd, is a measure of the strength of the interaction between a ligand and a receptor or between a substrate and an enzyme.
A high Ka value indicates a strong acid, while a low Ka value indicates a weak acid. In this case, the Ka value of 4.0 x 10⁴ for HNO₃ is relatively high.
To learn more about the dissociation constant, follow the link:
https://brainly.com/question/28197409
#SPJ6
Pressurized metal gas cylinders are generally used to store commonly used gases in the laboratory. At times, it can be easier to chemically prepare occasionally used gases. For example, oxygen gas can be prepared by heating KMnO4(s) according to the following chemical reaction:
2KMnO4(s) → K2MnO4(s) + MnO2(s) + O2(g)
How many grams of KMnO4 would you need to produce 0.27 moles of O2, assuming 100% conversion?
Answer:
You need 85.32 grams of KMnO₄ to produce 0.27 moles of O2, assuming 100% conversion.
Explanation:
The balanced chemical reaction is:
2 KMnO₄ (s) → K₂MnO₄ (s) + MnO₂ (s) + O₂ (g)
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles participate in the reaction:
KMnO₄: 2 molesK₂MnO₄: 1 moleMnO₂: 1 moleO₂: 1 moleThen you can apply the following rule of three: if by stoichiometry 1 mole of O₂ is produced by 2 moles of KMnO₄, 0.27 moles of O₂ are produced by how many moles of KMnO₄?
[tex]moles of KMnO_{4} =\frac{0.27 moles of O_{2} *2moles of KMnO_{4} }{1mole of O_{2} }[/tex]
moles of KMnO₄= 0.54
The molar mass of KMnO₄ is 158 [tex]\frac{g}{mol}[/tex].
Then the amount of mass present in 0.54 moles of the compound can be calculated by:
0.54 moles* 158.034 [tex]\frac{g}{mol}[/tex]= 85.32 grams
You need 85.32 grams of KMnO₄ to produce 0.27 moles of O2, assuming 100% conversion.
atomic number of element is 15 write a formula of an oxide
Answer:
Atomic Number. 15=phosphorus
Valency=3
So, Oxide=P203
Which equation represents a combustion reaction?
2SO2 + O2 → 2SO3
Pb(NO3)2 + 2HCl → PbCl2 + 2HNO3
2C2H6 + 7O2 → 4CO2 + 6H2O
Ca + 2HCl → CaCl2 + H2
Answer:
2SO2 + O2 => 2SO3
Explanation:
Combustion reaction involves heating of a compound/element/substance in presences of oxygen.
En una práctica experimental, para la obtención de cloruro cobaltoso, se hacen reaccionar 120 g de sulfuro cobaltoso de 60% de pureza con 30 cm3 de ácido nítrico concentrado (densidad 1,142 g/cm3, 69,8% en peso de HNO3), en presencia de ácido clorhídrico concentrado (densidad 1,19 g/cm3, 37,33 % en peso de HCl). Calcular:
a) El volumen de ácido clorhídrico concentrado que se requiere para la reacción.
b) La cantidad máxima de cloruro de cobalto (II) que se puede preparar.
c) El número de moléculas de monóxido de nitrógeno que se deprenden.
d) El número de átomos de azufre que se forman.
e) El número de moles de agua que se obtiene.
CoS + HNO3 + HCl → CoCl2 + NO + S + H2O
Answer: D
Explanation:
Utilicé traductor de español para responder esta pregunta
if B is completely insoluble in water. Your description should include the volume of solvent required.6b) Assuming that 2 mg of the impurity B are present along with 100 mg of A, describe how you can purify A if B has the same solubility behavior as A. Will one crystallization produce pure A
Answer:
1st step : mix the mixture with water that way A will dissolve while B will remain insoluble.
2nd step :To get B from the solution, filter the mixture and get B
3rd step : To get A from the solution evaporate the new solution
Explanation:
Assuming 2mg of impurity B to be present
100 mg of A is present as well
Method of purifying A given that B is of same solubility
Dissolve the 100 mg of A with 30 mL
1st step : mix the mixture with water that way A will dissolve while B will remain insoluble.
2nd step :To get B from the solution, filter the mixture and get B
3rd step : To get A from the solution evaporate the new solution
what is the atomic structure of an element that has atomic number of 11 and neutron number of 12.
Answer:
See explanation
Explanation:
The atomic number refers to the number of protons in the nucleus, it also tells us the number of electrons in the neutral atom since the atom is electrically neutral because the number of protons and electrons are equal.
If an atom has the atomic number 11, then the electrons in the atom are arranged in the shells in the order; 2, 8, 1.
Two electrons are found in the innermost shell, eight electrons are found in the next shell and one electron is found on the outermost shell.
The nucleus of the atom is composed of a total of 23 nucleons; 11 protons and 12 neutrons.
For the iron thiocyanate system, what is the value of the equilibrium constant, Kc, if the following are the concentrations of all species present. Provide your answer to three digits after the decimal.
FeSCN2+ 0.501
Fe3+ 0.494
SCN- 0.639
Answer:
Kc = 0.630
Explanation:
The equilibrium of the thiocyanate system occurs as follows:
FeSCN²⁺(aq) ⇄ Fe³⁺(aq) + SCN⁻(aq)
And equilibrium constant, kc, is:
Kc = [SCN⁻] [Fe³⁺] / [FeSCN²⁺]
Replacing with the gven concentrations:
Kc = 0.639M*0.494M / 0.501M
Kc = 0.630