Answer:
1) Endothermic.
2) [tex]Q_{rxn}=4435.04J[/tex]
3) [tex]\Delta _rH=15.8kJ/mol[/tex]
Explanation:
Hello there!
1) In this case, for these calorimetry problems, we can realize that since the temperature decreases the reaction is endothermic because it is absorbing heat from the solution, that is why the temperature goes from 22.00 °C to 16.0°C.
2) Now, for the total heat released by the reaction, we first need to assume that all of it is released by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:
[tex]Q_{rxn}=-(15.0g+250.0g)*4.184\frac{J}{g\°C}(16.0-20.0)\°C\\\\ Q_{rxn}=4435.04J[/tex]
3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case NH4Cl, we proceed as follows:
[tex]\Delta _rH=\frac{ Q_{rxn}}{n}\\\\\Delta _rH= \frac{ 4435.04J}{15.0g*\frac{1mol}{53.49g} } *\frac{1kJ}{1000J} \\\\\Delta _rH=15.8kJ/mol[/tex]
Best regards!
Best regards!
One method for preparing a nitrile is the dehydration of a primary amide.
a. True
b. False
Several elements must be transmuted to sea the real implications of this event
a.surpassed
b.estimated
c.changed
d.summed
thanks guys :)
What is the ratio by atoms of elements present in technetium (VII) peroxide? (peroxide
is a polyatomic ion)
1:7
2:8
4:9
3:1
Answer: 1:7
Explanation: 2 Tc^+7 + 7 O2^-2 -> Tc2 (O2)7
Also 2 Tc to 14 O
Pleaseee helpppp!!!!!!!!
Answer:
a covalent would be the two that are nonmetals
You are given three liquids, pentane (C5H12), water (H2O), and tetrachloromethane (CCl4), and are told to make solutions.
a. Predict whether you will be able to make a solution with pentane and tetrachloromethane
b. Predict whether you will be able to make a solution with pentane and water, and give your reasoning.
Answer:
A. predict whether you will be able to make a solution with pentane and tetrachloromethane
Explanation:
Sana nakatulong
The spinning of Earth on its axis is an example of its ________.
Answer:
rotation
Explanation:
Answer:
Rotation
Explanation:
Earth rotates on it's axis to give us the day and night cycle
arrange the following group of atoms in order of decreasing atomic size:B,Al,Ga
Answer:
B<Ga<Al
Explanation:
Hope this helps
which method is adopted in the seperation of lead chloride from water
Explanation:
by dissolving the mixture of lead sulphate and lead chloride in water we can separate the two. after dissolving the mixture on water lead sulphate can be obtained as the solid that 's left behind lead chloride can be recovered by evaporating.
What kind of waste is shown in the photograph?
A. Composted waste
B. E-waste
C. Hazardous waste
O D. Septic system waste
A moving 10 kilogram object has 20 Joules of kinetic energy. What is its velocity?
4 m/s
2 m/s
10 m/s
200 m/s
what is an example of an electrolyte solution?
Answer:
nacl with water
they are capable of conducting electricity
Which of the following is an example of synthesis?
A) HgO + Cl2-->HgCl + O2
B) Na + Br2 --> NaBr
C) KClO3 --> KCl + O2
D) Cl2 + NaBr --> NaCl + Br2
Answer:
B
Explanation:
what are the reasons that you cannot see many stars in the city nights?
Answer:
Because of the artificial lights influencing the dark night, turning it into a grey.
I am doing a exam in science need help.
What type of energy comes from the motion of tiny particles of matter?
Answer:
here you are
Explanation:
atomic energy
What type of Weathering is important to sand storms on Mars? Physical or
Chemical?
Why would 3D printing be important on Mars and why would you use material from the surface of Mars.
We could "print" things that we need on Mars.
We could print things that we need on Mars and use material that is already on the planet
It would be so cool
The cost would be less expensive.
Answer:
1. Physical Weathering
2. Option B
Explanation:
1. Physical weathering
On Mars, there are two types of weathering agents a) wind and b) acid fog. Thus, they will carry out only physical weathering
2. Option B
3D can be used to produce things that are required on the Mars and also the locally available raw material can be used for printing thereby saving the cost.
What would you do during a zombie apocalypse
A. run and hide
B. fight back
C. save some people
D. raid survivor's homes
E. keep your family alive
Answer:
C
Explanation:
because then you'd be able to make a group to raid, run with you, and save more people.
At some temperature for the equilibrium PX3(g) + X2(g) # PX5(g) the equilibrium constant is 0.74. At the same temperature the equilibrium constant for PX5(9) + PX3(g) X2(g) is
Answer: The equilibrium constant for [tex]PX_5(g)\rightarrow PX_3(g)+X_2(g)[/tex] is 1.35
Explanation:
Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as [tex]K_c[/tex]
For the given chemical reaction:
[tex]PX_3(g)+X_2(g)\rightarrow PX_5(g)[/tex]
The expression for [tex]K_c[/tex] is written as:
[tex]K_c=\frac{[PX_5]^1}{[PX_3]^1[X_2]^1}[/tex]
[tex]0.74=\frac{[PX_5]^1}{[PX_3]^1[X_2]^1}[/tex]
For the reverse chemical reaction:
[tex]PX_5(g)\rightarrow PX_3(g)+X_2(g)[/tex]
The expression for [tex]K_c'[/tex] is written as:
[tex]K_c'=\frac{[PX_3]^1[X_2]^1}{[PX_5]^1}[/tex]
[tex]K_c'=\frac{1}{K_c}=\frac{1}{0.74}=1.35[/tex]
The equilibrium constant for [tex]PX_5(g)\rightarrow PX_3(g)+X_2(g)[/tex] is 1.35
calculate the value of (Ag+) in a saturated solution of AgCl in distilled water
Answer:
[tex][Ag^+]=1.3x10^{-5}M[/tex]
Explanation:
Hello there!
In this case, according to the dissociation of silver chloride in aqueous solution, we can write:
[tex]AgCl(s)\rightarrow Ag^+(aq)+Cl^-(aq)[/tex]
Whereas the equilibrium expression is:
[tex]Ksp=[Ag^+][Cl^-][/tex]
And the solubility product constant is 1.7 x10⁻¹⁰; thus, by inserting x as the concentration of both silver and chloride ions as they are the same at equilibrium, we obtain:
[tex]1.7x10^{-10}=x^2\\\\x=\sqrt{1.7x10^{-10}} \\x=1.3x10^{-5}M[/tex]
Which is also equal to the concentration silver ions at equilibrium in a saturated solution because we considered the Ksp.
[tex][Ag^+]=1.3x10^{-5}M[/tex]
Best regards!
which is the most fluorescent molecule?
How many grams are in 3.0 moles of sodium chloride (NaCl)?
Answer:
175.5
Explanation:
how many ions does magnesium phosphite have? how many of those are anions? please explain thought process.
Answer:
We can simply refer to the cation in the ionic compound as magnesium. Phosphorus, Pstart text, P, end text, is a group 15 element and therefore forms 3- anions.
Explanation:
Because it is an anion, we add the suffix -ide to its name to get phosphide as the name of the ion.
Write a formula and balanced equation for the following: solid copper metal reacts with aqueous silver nitrate to produce solid silver metal and aqueous copper Nitrate. How do I know if it will form copper (I) nitrate CuNO3 or copper (II) nitrate Cu(NO3)2 ?
Explanation:
copper (II) nitrate
Illustrate variety of substances of which an element can be part:
metal --> blue solution --> blue solid --> black solid --> blue solution (again) --> metal (again).When solid copper reacts with aqueous silver nitrate, the products are copper (II) nitrate and solid silver. and carbon monoxide gas produces solid iron and carbon dioxide gas.
Which element had the smallest atomic radius
Answer:
helium is the answer
Explanation:
helium is the smallest element in francium is the largest hope this helps
Which fossil fuel was formed from the bodies of prehistoric animals and plants?
Answer:
coal
Explanation:
which of the following, when dissolved in water, forms a weak acid.A. HNO3B. HClO4C. HBrD. HClOE. NH3
Answer:
The weak acid is - E. [tex]NH_3[/tex]
Explanation:
Ammonia is a strong base, which in turn make it to be a weak acid.
As, the rest of the options are acid and therefore furnish hydrogen ions when dissolved in water, making them strong acid.
And ammonia dissolves in water to form its conjugate ammonium ion and hydroxide ion, therefore making the solution basic.
Hence, from the given options, the correct option is E. [tex]NH_3[/tex]
The compound which when dissolved in water, forms a weak acid is; Choice E: NH3
According to the question;
we are required to determine which compound forms a weak acid when dissolved in water.Unlike other compounds (HNO3, HClO, HBr, HClO) which dissolve in water to yield H+ ion, Ammonia dissolves in water to form ammonium ion and hydroxide ion, OH-.
In essence, NH3 is a strong base when dissolved in water and consequently, is a weak acid when dissolved in water.
Read more:
https://brainly.com/question/15192126
Which one is it for a brialiest
1. What organ system is responsible for controlling all of the body
functions?
Answer:
The human brain is the body's control center, receiving and sending signals to other organs through the nervous system and through secreted hormones. It is responsible for our thoughts, feelings, memory storage and general perception of the world. The human heart is a responsible for pumping blood throughout our body
why do we need digital technology in school?
Answer: See explanation
Explanation:
Digital technologies refers to the electronic tools, or devices that can be used to generate data, store them or process data. e.g. mobile phones, ebooks etc.
Digital learning makes use of technology. Effective use of digital learning tools can help increase the engagement of students. This csn.aksi be used by the teachers to enhance personalized learning and also improve the lesson plans.
Digital technology can enhance collaboration, and communication with the students. The use of videos, robots, virtual classrooms, augmented reality and other technologies can bring about fun and foster inquisitiveness.
What are the benefits of Fluoride?
Answer:
The benefits of Fluoride are rebuild (remineralize) weakened tooth enamel.slow down the loss of minerals from tooth enamel.reverse early signs of tooth decay.prevent the growth of harmful oral bacteria
Answer:
Fluoride is often called nature's cavity fighter and for good reason. Fluoride, a naturally-occurring mineral, helps prevent cavities in children and adults by making the outer surface of your teeth (enamel) more resistant to the acid attacks that cause tooth decay.
Why do scientists think that liquid water might have once existed on Mars?
Answer: The discovery of three buried lakes. Scientists think that a long time ago there were lakes and rivers, etc on Mars. Now of course, you can't see any visible water sources on the surface.
Answer:
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere.[5] What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae may be grains of flowing sand and dust slipping downhill to make dark streaks.The only place where water ice is visible at the surface is at the north polar ice cap. Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole and in the shallow subsurface at more temperate conditions. More than 5 million km3 of ice have been detected at or near the surface of Mars, enough to cover the whole planet to a depth of 35 meters. Even more ice is likely to be locked away in the deep subsurface.
Some liquid water may occur transiently on the Martian surface today, but limited to traces of dissolved moisture from the atmosphere and thin films, which are challenging environments for known life. No large standing bodies of liquid water exist on the planet's surface, because the atmospheric pressure there averages just 600 pascals , a figure slightly below the vapor pressure of water at its melting point; under average Martian conditions, pure water on the Martian surface would freeze or, if heated to above the melting point, would sublime to vapor. Before about 3.8 billion years ago, Mars may have had a denser atmosphere and higher surface temperatures, allowing vast amounts of liquid water on the surface, possibly including a large ocean that may have covered one-third of the planet.Water has also apparently flowed across the surface for short periods at various intervals more recently in Mars' history. Aeolis Palus in Gale Crater, explored by the Curiosity rover, is the geological remains of an ancient freshwater lake that could have been a hospitable environment for microbial life.Many lines of evidence indicate that water ice is abundant on Mars and it has played a significant role in the planet's geologic history.The present-day inventory of water on Mars can be estimated from spacecraft images, remote sensing techniques (spectroscopic measurements, radar, etc.), and surface investigations from landers and rovers.Geologic evidence of past water includes enormous outflow channels carved by floods, ancient river valley networks, deltas and lakebeds,and the detection of rocks and minerals on the surface that could only have formed in liquid water. Numerous geomorphic features suggest the presence of ground ice (permafrost)and the movement of ice in glaciers, both in the recent past and present. Gullies and slope lineae along cliffs and crater walls suggest that flowing water continues to shape the surface of Mars, although to a far lesser degree than in the ancient past.Although the surface of Mars was periodically wet and could have been hospitable to microbial life billions of years ago, the current environment at the surface is dry and subfreezing, probably presenting an insurmountable obstacle for living organisms. In addition, Mars lacks a thick atmosphere, ozone layer, and magnetic field, allowing solar and cosmic radiation to strike the surface unimpeded. The damaging effects of ionizing radiation on cellular structure is another one of the prime limiting factors on the survival of life on the surface. Therefore, the best potential locations for discovering life on Mars may be in subsurface environments. Large amounts of underground ice have been found on Mars; the volume of water detected is equivalent to the volume of water in Lake Superior. In 2018, scientists reported the discovery of a subglacial lake on Mars, 1.5 km (0.93 mi) below the southern polar ice cap, with a horizontal extent of about 20 km (12 mi), the first known stable body of liquid water on the planet.Understanding the extent and situation of water on Mars is vital to assess the planet’s potential for harboring life and for providing usable resources for future human exploration. For this reason, "Follow the Water" was the science theme of NASA's Mars Exploration Program (MEP) in the first decade of the 21st century. NASA and ESA missions including 2001 Mars Odyssey, Mars Express, Mars Exploration Rovers (MERs), Mars Reconnaissance Orbiter (MRO), and Mars Phoenix lander have provided information about water's abundance and distribution on Mars.Mars Odyssey, Mars Express, MRO, and Mars Science Lander Curiosity rover are still operating, and discoveries continue to be made.
