Answer:
option is (b)
Explanation:
please mark me as brilliant
1. With the aid of a Hess cycle, determine the enthalpy of the decomposition reaction of sodium nitrate, NaNO3 to sodium nitrite, NaNO2 and oxygen, O2. [5]
Enthalpy of formation of NaNO3 = -468 kJ/mol
Enthalpy of formation of NaNO2 = -369kJ/mol
Answer:
Explanation:
2NaNO₃ = 2NaNO₂ + O₂
NaNO₃ = NaNO₂ + 1/2 O₂
- 468 kJ -369 kJ 0 kJ
enthalpy of decomposition reaction
= - 369 - ( - 468 ) kJ
= 99 kJ / mol .
What characteristic of life is demonstrated by maintaining a stable pH?
Answer:
Living Things Maintain Stable Internal Conditions When any living organism gets thrown off balance, its body or cells help it return to normal. In other words, living organisms have the ability to keep a stable internal environment. Maintaining a balance inside the body or cells of organisms is known as homeostasis.
Explanation:
Which pattern on the periodic table is correctly predicted below?
Groups determine the number of valance electrons and periods determine the number of energy levels
Groups determine the number of energy levels and periods determine the number of valence electrons
Groups determine the number of protons, and periods determine energy levels
Groups determine the number of neutrons, and periods determine valence
Plzz
Matter is anything that has mass and takes up space (volume). How does volume change as matter changes state?
A. The density of matter remains the same, only energy of the atoms changes.
B. matter becomes more dense as it moves from solid to gas
C. Matter becomes less dense as it moves from gas to solid state
D. Matter becomes more dense as it moves from gas to solid state
Answer: D) Matter becomes more dense as it moves from gas to solid state
A gas expands to fill up the container of whatever shape or size. As it cools to a solid, the molecules get closer together and don't move as much (the molecules still will vibrate and move somewhat even in solid form). So effectively the volume of the object shrinks while the amount of mass stays the same. This is why the density increases when going from gas to solid.
Gustavo and Beatriz are pushing on a door in opposite
directions. If the door does not move, the forces are
The net force in this scenario would be Answer: balanced and zero
Answer:
Correct
Explanation:
Balanced forces are always zero!
Answer:
Balanced
Zero
Explanation:
Polonium crystallizes in a simple cubic unit cell with an edge length of 3.36 Å.
a. What is the mass of the unit cell?
b. What is the volume of the unit cell?
c. What is the density of polonium?
a. The unit cell is the smallest group of atom which have overall symmetry of a crystal, and from which is the entire letters can be buled built up by repetition in 3 dimensions.
b. The volume(v) of the unit cell is equal to the cell edge length (a)cubed.
c. density of polonium is 9.32g/cm3.
Write the net ionic equation for the acid-base reaction
PH3(aq) + HCl(aq) - PH4Cl(aq)
Explanation:
i dont understand dont you already have the equation?
The net ionic equation for the acid-base reaction PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq) is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .
What is net ionic equation?Chemical reaction equations can be written in a variety of ways. Unbalanced chemical equations, which identify the species involved, balanced chemical equations, which identify the number and type of species, molecular equations, that also express compounds as molecules rather than component ions, and net ionic equations, which only address the species which contribute to a reaction, are some of the most popular.
A chemical equation for just a process known as the net ionic equation only includes the species that are really involved in the reaction.
PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq)
PH[tex]_3[/tex](aq) + H⁺ (aq) + Cl⁻ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ (aq) + Cl⁻ (aq)
PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺
Therefore, the net ionic equation for the acid-base reaction is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .
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which type of rection has the general formuial ab+cd
Which of the following aqueous solutions has the lowest pH? Why?
a. 0.1 M HCl;
b. 0.1 M acetic acid (pKa = 4.86);
c. 0.1 M formic acid (pKa = 3.75
Please help
It’s super quick
Answer:
1. a
Explanation:
2. c
Answer:
1 is A number two is C
Whenever the same two elements form more than one
compound, the different masses of one element that combine
with the same mass of the other element are in the ratio of
small whole numbers.
TRUE
FALSE
Answer:
The answer is true
Explanation: Because The law of multiple proportions states that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.
A neutral atom becomes a positive ion when it
Answer:
Neutral atoms can be turned into positively charged ions by removing one or more electrons.
Explanation:
If there is an atom that has 9 protons and 9 electrons, removing an electron from the atom will gain a postive charge.
What volume of 0.150 M 2 M Li2S solution is required to completely react with 120 mLmL of 0.150 M Co(NO3)2 MCo(NO3)2
Answer:
Explanation:
M1V1=M2v2
M1=0.150M
M2=0.150M
V2=120*10^-3
V1=M2V2/M1
V1=0.150*120*10^-3/0.150
V1=0.12
0.12 mL volume of 0.150M 2M Li₂S solution is required to completely react with 120 mL of 0.150M Co(NO₃)₂ MCo(NO₃)₂.
What is the relation of volume with molarity?
With M1 and M2 representing the molarity of the solutions, expressed as mol/L or M, and V1 and V2 representing their respective volumes, this calculator may be used to calculate a missing number for the dilution equation.
A solution's concentration is determined by multiplying its volume by its molarity (M1V1 = M2V2) On both sides of the equation, the units should stay the same.
Here
M₁V₁=M₂V₂
M₁=0.150M
M₂=0.150M
V₂=120 × 10⁻³
V₁=M₂V₂/M₁
V₁=0.150 × 120 × 10⁻³/0.150
V₁=0.12.
Therefore, 0.12 mL volume of 0.150M 2M Li₂S solution is required to completely react with 120 mL of 0.150M Co(NO₃)₂ MCo(NO₃)₂.
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The amount of force needed to keep a 10 kg box moving at a constant
speed of 0.4 m/s on frictionless ice is *
ON,
0.04N
40 N
1.4 N
Answer:
ON
Explanation:
Frictional force is a force that opposes the motion of body. It is because of friction that motion can be controlled and even walking is made possible.
Now, on a frictionless surface, there is no opposition to motion. Therefore, to keep the body moving there is no force required.
If surface lacks friction, motion will continue perpetually without any hinderance.What is the relationship between temperature and pressure
A binary molecule consists of how many atoms?
O1
02
3
4
Answer:
2
Explanation:
BIonary bi means 2
i hope this helps :)
A rock rolls down a hill. Which form of energy is this an example of?
Chemical
Electrical
Mechanical
Thermal
Answer:
Mechanical
Explanation:
chemical
Explanation:
I took test 2020
When is a chemical equation considered balanced
Answer:
If each side of the equation has the same number of atoms of a given element, that element is balanced. If all elements are balanced, the equation is balanced.
Explanation:
What is the oxidation number of P in PF6−?
What is the name of the process that is used to clean up environmental waste and how does it work?
Answer:
Environmental cleanup includes removal of heavy metals and other toxic contaminants from the environment and the process is called remediation.
Name 2 ways heat can be transferred through convention.
Answer:
Heat can travel from one place to another in three ways: Conduction, Convection and Radiation. Both conduction and convection require matter to transfer heat. If there is a temperature difference between two systems heat will always find a way to transfer from the higher to lower system.
Explanation:
Which method of heat transfer allows you to fry an egg in a frying pan on the stove?
Answer:
Conduction
Explanation:
Answer:
Conduction is correct
Explanation:
i will give the first person brainliest! please helppp
okay so the Answer is c
PLEASE HELP!! (I will mark brainiest) (REAL ANSWERS ONLY PLEASE!)
In one paragraph, using your own words, describe the structure of DNA using the following terms: phosphate, sugar, pyrimidines, purines, and bonding.
The phosphate group of one nucleotide bonds covalently with the sugar molecule of the next nucleotide, and so on, forming a long polymer of nucleotide monomers. The sugar–phosphate groups line up in a “backbone” for each single strand of DNA, and the nucleotide bases stick out from this backbone. The carbon atoms of the five-carbon sugar are numbered clockwise from the oxygen as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate group is attached to the 5′ carbon of one nucleotide and the 3′ carbon of the next nucleotide. In its natural state, each DNA molecule is actually composed of two single strands held together along their length with hydrogen bonds between the bases.
Answer:
Explanation:
The discovery that DNA is the prime genetic molecule, carrying all the hereditary information within chromosomes, immediately focused attention on its structure. It was hoped that knowledge
of the structure would reveal how DNA carries the genetic messages that are replicated when chromosomes divide to produce two identical copies of themselves. During the late 1940s and early 1950s, several research groups in the United States and in Europe engaged in serious efforts—both cooperative and rival—to understand how the atoms of DNA are linked together by covalent bonds and how the resulting molecules are arranged in three-dimensional space. Not surprisingly, there initially were fears that DNA might have very complicated and perhaps bizarre structures that differed radically from one gene to another. Great relief, if not general elation, was thus expressed when the fundamental DNA structure was found to be the double helix. It told us that all genes have roughly the same three-dimensional form and that the differences between two genes reside in the order and number of their four nucleotide building blocks along the complementary strands.
Now, some 50 years after the discovery of the double helix, this simple description of the genetic material remains true and has not had to be ap- preciably altered to accommodate new findings. Nevertheless, we have come to realize that the structure of DNA is not quite as uniform as was first thought. For example, the chromosome of some small viruses have single-stranded, not double-stranded, molecules. Moreover, the precise orientation of the base pairs varies slightly from base pair to base pair in a manner that is influenced by the local DNA sequence. Some DNA se- quences even permit the double helix to twist in the left-handed sense, as opposed to the right-handed sense originally formulated for DNA’s general structure. And while some DNA molecules are linear, others are circular. Still additional complexity comes from the supercoiling (further twisting) of the double helix, often around cores of DNA-binding proteins.
Likewise, we now realize that RNA, which at first glance appears to be very similar to DNA, has its own distinctive structural features. It is principally found as a single-stranded molecule. Yet by means of intra-strand base pairing, RNA exhibits extensive double-helical character and is capable of folding into a wealth of diverse tertiary structures. These structures are full of surprises, such as non-classical base pairs, base-backbone interactions, and knot-like configurations. Most remarkable of all, and of profound evolutionary significance, some RNA molecules are enzymes that carry out reactions that are at the core of information transfer from nucleic acid to protein.
Clearly, the structures of DNA and RNA are richer and more intricate than was at first appreciated. Indeed, there is no one generic structure for DNA and RNA. As we shall see in this chapter, there are in fact vari- ations on common themes of structure that arise from the unique physi- cal, chemical, and topological properties of the polynucleotide chain
is the movement of particles from an area of higher concentration to an area of lower concentration
Answer:
The answer is Diffusion.
Answer:
Hypertonic
Explanation:
predict how many moles of nh3 would be made if 6.00 moles of h2 were used N2
Answer:
4 moles
Explanation:
The equation is 3H2 + N2 → 2NH3
so the ratio of moles would be
2:3 or 2/3
so 6*2/3 which is 4
hope this helped.
Answer:
4moles
Explanation:
Given parameters:
Number of moles of H₂ used = 6moles
Equation of the reaction:
N₂ + 3H₂ → 2NH₃
3 mole of H₂ was used to produce 2 mole of NH₃;
6 mole of H₂ will produce [tex]\frac{6x2}{3}[/tex] = 4 moles of NH₃
The number of moles of NH₃ produced is 4moles
1 point
Which element requires the least amount of energy to remove its valence electron(s)?
barium
chlorine
oxygen
carbon
What most likely to cuase the rate of a chemical reaction to increase
Answer:
An increase on temperature.
Explanation:
Answer: adding a catalyst or increasing temperature
Explanation:
The density of ethanol, C 2H 5OH, is 0.789 g/mL. How many milliliters of ethanol are needed to produce 25.0 g of CO 2 according to the following chemical equation?
C 2H 5OH( l) + 3 O 2( g) → 2 CO 2( g) + 3 H 2O( l)
Answer:
11.1mL
Explanation:
The reaction expression is given as:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Given parameters:
density of ethanol = 0.789g/mL
mass of CO₂ = 25g
Unknown:
Volume of ethanol = ?
Solution:
First find the number of moles of the CO₂ from the given mass;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of CO₂ = 12 + 2(16) = 44g/mol
Number of moles = [tex]\frac{25}{44}[/tex] = 0.57mol
Then;
Find the number of moles of ethanol used;
3 moles of CO₂ is produced from 1 mole of ethanol;
0.57mole of CO₂ will be produced from [tex]\frac{0.57}{3}[/tex] = 0.19mole of ethanol
Now;
Find the mass of the ethanol from the given mole;
Mass of ethanol = number of moles x molar mass
Molar mass of ethanol = 2(12) + 5(1) + 16 + 1 = 46g/mol
Mass of ethanol = 0.19 x 46 = 8.74g
Then;
Density is the mass per unit volume of a substance;
Density = [tex]\frac{mass}{volume}[/tex]
Volume = [tex]\frac{mass}{density}[/tex]
Volume = [tex]\frac{8.74}{0.789}[/tex] = 11.1mL
Two moles of acetyl chloride was mixed with two moles of dimethylamine. After the reaction is complete, what species can be found in the mixture
Answer:
See explanation
Explanation:
The reaction is shown in the image attached. This reaction occurs by a carbocation (ionic) mechanism.
The lone pair on the nitrogen atom attacks the carbocation leading to the formation of the product as shown in the image attached.
Since the reaction occurs in a 1:1 ratio, two moles of reactants yields two moles of product.
