Answer:
1. more
2. less
3. more
4. less
Explanation:
A number is three times the difference between twenty and the number. What is the number?
Answer:
the number is 7
Explanation:
"Three times" means multiply by 3
"Difference" means subtract
"Sum" means add
3(x - 7) = 23 - (3x + 2)
3x - 21 = 23 - 3x - 2
3x - 21 = 21 - 3x
6x = 42
x = 7
What is the quantity of heat evolved when 15g of CH4 is completely burned in air? Given that CH4+2O2→ CO2+2H2OΔH=-890Kj/mol
Answer:
You're going to have to convert the grams to moles, and then multiply that with the ratio of heat produced to the ratio of CH4
ort
Which is a primary alcohol?
0 3-pentanol
2-propanol
1-ethanol
4-octanol
urvey
Lig A Moving to another question will save this response.
Answer:
1 ethanol is right answer
Explanation:
CH3- CH2-OH
Which of the following statements accurately describes how a catalyst acts in a chemical reaction?
I. Decreases the kinetic energy of the reaction
II. Is not consumed by the reaction
III. Increases the equilibrium constant
IV. Reduces the required activation energy
a) II, III, and IV only
b) I and III only
c) I and II only
d) II and IV only
Answer:
d) II and IV only.
Explanation:
A catalyst increases the kinetic energy of reactant molecules which increases the magnitude of collision. These then decreases the activation energy . A catalyst is not consumed by reaction because it is neither reactant nor a product, hence has no effect on equilibrium constant.
[tex].[/tex]
Answer:
A
Explanation:
it speed up a chemical reaction without being consumed by the reaction and increases the reaction rate by lowering the activation energy for a reaction but the average kinetic energy of the molecules remains the same well the required energy decreases
Rewrite this measurement with a simpler unit, if possible.
4.5·m2m2m
Answer:
why are people s opinions and prejudices her greatest obstacles
A change in direction in a wave when it passes through an opening is called
Answer:
Refraction
Explanation:
the change in direction of waves that occurs when waves travel from one medium to another. ... Diffraction is the bending of waves around obstacles and openings. The amount of diffraction increases with increasing wavelength
Answer:
A change in direction in a wave when it passes through an opening is called diffraction.
I hope this helps
In the reaction A + B + C + D, what are the reactants?
O A. Just B
B. Cand D
O c. A and B
O D. A and C
Answer:
C.
Explanation:
I believe that it should be A and B.
Which option is an isotope with 6 protons and 8 neutrons? (1 point)
O oxygen-6
o carbon-14
o oxygen-14
o carbon-8
Answer:
Carbon-14
Explanation:
It is because it have 6 protons and 8 neutrons which are added together to form an atomic mass of 14.
The mass number of an isotope is the sum of the number of protons and number of neutrons hence the correct answer is carbon-14.
Isotopes are atoms of the same element that has the same number of protons but different number of neutrons.
The atomic number is the same as the number of protons in the atom. Since there are six protons in the atom, the element must be carbon.
There are eight neutrons meaning that the mass number is 8 + 6 = 14
Therefore, the isotope is carbon-14.
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1. Consider the following thermochemical reaction for kerosene:
2 C12H26(l) + 37 O2(g) 24 CO2(g) + 26 H2O(l) + 15,026 kJ
(a) When 21.3 g of CO2 are made, how much heat is released?
(b) If 500.00 kJ of heat are released by the reaction, how grams of C12H26 must have been consumed ?
(c) If this reaction were being used to generate heat, how many grams of C12H26 would have to be reacted to generate
enough heat to raise the temperature of 750g of liquid water from 10oC to 90oC?
2. Consider the reaction: NaNO3(s) + H2SO4(l) → NaHSO4(s) + HNO3(g) ΔH° = 21.2 kJ
How much heat must absorbed by the reaction system to convert 100g of NaNO3 into NaHSO4(s)?
3. What is the enthalpy change when 49.4 mL of 0.430 M sulfuric acid reacts with 23.3 mL of 0.309 M potassium
hydroxide?
3.
H2SO4(aq) + 2KOH(aq) → K2SO4(aq) + 2H2O(l) ΔH° = –111.6 kJ/mol
do you have the specific heat for part 2?
What best describes the goals of scientific investigation and technological development?
Both scientific investigation and technological design aim to solve problems by making more cost-effective and affordable products.
Both scientific investigation and technological design aim to conduct experiments to uncover new information and share the results.
Scientific investigation aims to design products that can make use of new information, whereas technological development aims to conduct experiments to improve affordability and availability.
Scientific investigation aims to design and implement an experiment to learn new information, whereas technological development aims to design a product to solve a problem.
Answer: D. Scientific investigation aims to design and implement an experiment to learn new information, whereas technological development aims to design a product to solve a problem.
Explanation:
The surface of silver metal, Ag(s), became tarnished when it was exposed to oxygen, producing Ag2O. In Ag2O, the oxidation state of silver is 1. According to this information, silver metal was _____. Please choose the correct answer from the following choices, and then select the submit answer button. Answer choices reduced
Answer: The silver metal was OXIDIZED.
Explanation:
OXIDATION is defined as loss of electrons and increase in oxidation number of an atom.
Oxidation number is the charge on an ion in an ionic compound or the charge that an atom in a covalent compound would have it it were ionic. There are basic rules governing oxidation number, they include:
--> the oxidation number of elements in their free states is ZERO. Example O2, Cl2,Na, Al, Ag.
-->The oxidation number for an ion is the same as the size and sign of the charge on the ion. For example the oxidation number of Zn2+ is +2.
--> the sum of all the oxidation numbers of the elements in a compound is zero.
--> oxidation numbers are always written with either a positive or a negative sign.
On the other hand, reduction is the opposite of oxidation. As oxidation is taking place, reduction is also taking place. Reduction involves:
--> Gain of electron and
--> decrease in oxidation number
From the question, the silver metal had ZERO as it's oxidation number because it's in free state. After being exposed to oxygen to form silver oxide, the oxidation number became +1.
Since there is an increase in the oxidation number, the silver metal was OXIDIZED
which are the nutrients essential to us
Explanation:
carbohydrate,fat,protein, vitamin, mineral, water
Answer:
There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water.
Given the reactants of the chemical reaction that will take place in Part D (construction of a lead concentration cell) prior to the assembly of the cell, determine the type of chemical reaction it is. Hint: Determine the products of the reaction.
Answer:
hi
Explanation:
Which of the following is an example of a scientific theory?
Matter can be neither created nor destroyed.
Force equals mass times acceleration.
Matter behaves the way it does because it is made of atoms.
There is probably life on Mars.
C. Matter behaves the way it does because it is made of atoms.
Answer:
Matter can neither be created nor destroyed
Explanation:
Mark me. as brainliest
Draw Lewis structures to show how H+ is transferred when HNO₂ and NH₃ react with each other. The Lewis structure of HNO₂ is:
Attached are the Lewis structures:
Hope it helps...
[tex] \: \: \: [/tex]
Are acids harmful to work with.
Answer:
yes it is
Explanation:
because there are some acid which really harm skin.
Why must beta particles be used to detect leaks in a pipe?
Why must beta particles be used to detect leaks in a pipe?
A. Beta particles will not be absorbed by the soil like gamma radiation, but won't pass through the pipe before reaching the leak like alpha radiation would.
B. Beta particles will not cause an electrical discharge like alpha particles when they interact with the metal pipe, or contaminate the water like gamma radiation.
C. Beta particles are not used, only alpha particles are used because they are not harmful to humans.
D. Beta particles will not be absorbed by the soil like alpha particles, but won't pass through the pipe before reaching the leak like gamma radiation would.
Should be D, because alpha particles are absorbed by soil and gamma isn't
Beta particles will not be absorbed by the soil like alpha particles, but won't pass through the pipe before reaching the leak.
What is Beta particle?This type of particle is a high-speed electron and is derived from the process of beta decay.
It is used to detect leaks in pipe because it will not be absorbed by the soil like alpha particles, but won't pass through the pipe before reaching the leak like gamma radiation would.
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One of the electron transitions in a hydrogen atom produces infrared light with a wavelength of
8.231 x 10°m. What amount of energy causes this transition?
A transition occurs when an electron absorbs energy and moves from one energy level to another.
Let us recall the formula;
E = hc/λ
h= planks constant = 6.6 * 10^-34 Js
c = speed of light = 3 * 10^8 ms-1
λ = wavelength =
We can see from the question that the exponent in the value for the wavelength was not properly rendered hence we can not be able to substitute values and obtain a numerical answer for the energy of the infrared radiation.
However, if all the values are properly substituted, then the energy of the infrared radiation can conveniently be obtained.
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Write chemical equations for the reactions that occur when solutions of the following substances are mixed:
c. OH- and H₂PO₄-
d. C₅H₅N pyridine, a base) and HC₂H₃O₂ (acetic acid)
#c
[tex]\\ \rm\hookrightarrow H_2PO_4^-+OH-\longrightarrow HPO_4^{2-}+H_2O[/tex]
H_2PO_4 is a base according to bronsted Lowry theory.So it loses a H+ and OH- takes that to form water#2
[tex]\\ \rm\hookrightarrow C_5H_5N+C_2H_4O_2\longrightarrow C_6H_6N^++C_2H_3O_2^-[/tex]
Pyridine is a bronsted base .So it forms pyridine cation by taking one H^+ from acetic acidAssuming that no equilibria other than dissolution are involved, calculate the concentration of all solute species in each of the following solution of salt in contact with a solution containing a common ion. Show that changes in the initial concentrations:
PbCl2(s) in 0.631 M MgCl2 (MgCl2 is strong electrolyte)
Ksp PbCl2 = 1.6 × 10−5
The concentration of all solute species in the solution are:
[tex][Mg^{2+} ] = 0.631 M \\ [Pb] = 1.0 \times 10^{-5} M \\[Cl^{-} ] = 1.26 M[/tex]
MgCl₂ (0.631 M) is a strong electrolyte that dissociates according to the following equation.
MgCl₂(aq) ⇒ Mg²⁺(aq) + 2 Cl⁻(aq)
Considering the molar ratios, the initial concentrations of Mg²⁺ and Cl⁻ are:
[tex]\frac{0.631 mol MgCl_2}{L} \times \frac{1molMg^{2+} }{1molMgCl_2} = \frac{0.631molMg^{2+}}{L} \\\frac{0.631 mol MgCl_2}{L} \times \frac{2molCl^{-} }{1molMgCl_2} = \frac{1.26molCl^{-}}{L}[/tex]
Cl⁻ is a common ion between MgCl₂ and PbCl₂. To consider the solution equilibrium for PbCl₂ (a sparingly soluble salt), we will make an ICE chart.
PbCl₂(s) ⇄ Pb²⁺(aq) + 2 Cl⁻(aq)
I 0 1.26
C +x +2x
E x 1.26+x
The solubility product constant, Ksp, is:
[tex]Ksp = 1.6 \times 10^{-5} = [Pb^{2+} ][Cl^{-} ]^{2} = (x) (1.26+x)^{2}[/tex]
Since 1.26 >>> x, 1.26 + x ≈ 1.26.
[tex]Ksp = 1.6 \times 10^{-5} = (x) (1.26)^{2}\\x = 1.0 \times 10^{-5}[/tex]
The concentration of all solute species in the solution are:
[tex][Mg^{2+} ] = 0.631 M\\ [Pb] = x = 1.0 \times 10^{-5} M\\[Cl^{-} ] = 1.26+x = 1.26 M[/tex]
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arrange the metals sodium,copper, and magnesium in the decreasing order of their reactivity
Answer:
sodium>magenisium>copper
Which of the following metals will liberate hydrogen from dilute HCL? A. Ag B.Au C.Hg D.Sn
Answer:
ag and au are sure not to react. but hg and sn might or might not
Help please due tomorrow
Answer:
3rd option - humans chose the potential parents for crosses based on desired characteristics.
Explanation:
Artificial selection is the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations.
HELP! Which type of model best represents simple molecules?
A. wire
B. ribbon
C. structural formula
D. Lewis dot
Convert the concentration of 0.700 M Na2SO4 to g/mol
To convert from mass concentration to molar concentration we use the formula;
Mass concentration = molar concentration * molar mass
Molar concentration of Na2SO4 = 0.700 M
Molar mass of Na2SO4 = 2(23) + 32 + 4(16) = 142 gmol-1
Hence;
Mass concentration = 0.700 M * 142 gmol-1
Mass concentration = 99.4 g/mol
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Which substance will sublimate when in the solid phase at room temperature and pressure?
Select the correct answer below:
A) carbon dioxide
B) water
C) mercury
D) helium
Answer:
I think carbon dioxide is right answer
In water, a substance that ionizes completely in solution is called a
Answer:
please mark me brainliest
Explanation:
In water, a substance that ionizes completely in solution is called a weak electrolyte.
Answer: strong electrolyte.
Explanation: In water, a substance that ionizes completely in solution is called a. a. weak electrolyte.
Name the following alkane molecule:
A. methylpentane
B. 2-methylpentane
C. 2-ethylpentane
Answer:
B
Explanation:
its upside down but I'm 99% sure
Sodium ethoxides are made by direct reaction of:
a. Sodium hydroxide and dry ethanol
b. Sodium metal and 70% ethanol
c. Sodium hydroxide and 70% ethanol
d. Sodium metal and dry ethanol
Answer:c
Explanation:
why styrene undergoes and ionic polymerization at a faster rate than p methoxystyrene
Answer:
In styrene, there is a phenyl group which is electron-withdrawing. So the electronic density in the double bonds increases, hence easy to associate as monomers. While in methoxystyrene, there is a carbonyl group which is not electron deficient. so no easy association with monomers.
Explanation:
[tex]{ \sf{styrene \: is \: phenylethene \: }} \\ { \sf{its \: polymer \: is \: polystyrene}}[/tex]
