Which of the following processes is exothermic? which of the following processes is exothermic? the chemical reaction in a "cold pack" often used to treat injuries the vaporization of water?
Answer:
Among the processes given i.e. Burning of candle, baking of bread, the reaction in a cold pack, and vaporization of water. The burning of the candle is an exothermic reaction.
Explanation:
The exothermic reactions are the ones in which there is an emission of energy.
In the baking of bread, the process grasps the energy and utilized it for the baking process. This is the form of an endothermic reaction.
The reaction of a cold pack for the treatment of injuries requires the heat from the surroundings and convert it to heat for recovery. So this requires energy and there is no loss in surroundings. It can't be the exothermic reaction.
The vaporization of water requires heat energy for transmission to the vapor state. This does not emit energy. This can't be the exothermic reaction.
The burning of Candle emits heat energy in the surroundings. This is considered an exothermic reaction.
For more information, refer the link:
https://brainly.com/question/10373907?referrer=searchResults
Lithium hydroxide is used to purify air by removing carbon dioxide. a 25.00ml sample of lithium hydroxide solution is titrated to an end point by 15.22 ml of a 0.3340m hydrochloric acid solution. what is the molarity of the lioh solution
A chemical supply company sells a concentrated solution of aqueous h2so4 (molar mass 98 g mol−1 ) that is 50. percent h2so4 by mass. at 25°c, the density of the solution is 1.4 g ml−1 . what is the molarity of the h2so4 solution at 25°c?
is h2c2o4 an Arrhenius base or arrhenius acid
H₂C₂O₄, or oxalic acid, is an Arrhenius acid because it dissociates in water to produce hydrogen ions.
H₂C₂O₄, also known as oxalic acid, is an Arrhenius acid, not an Arrhenius base. An Arrhenius acid is defined as a compound which ionizes to yield hydrogen ions (H+) in aqueous solution, whereas an Arrhenius base ionizes to yield hydroxide ions (OH-). Since H₂C₂O₄ dissociates in water to produce two H+ ions and the oxalate ion (C₂O₄-), it increases the H+ ion concentration, making it an acid according to Arrhenius's definition.
What most determines the entropy of a solid? A. The mobility of electrons in the solid B. The crystalline structure of the solid C. The specific heat capacity of the solid D. The enthalpy of formation of the solid
Answer:
The crystalline structure of the solid
Explanation:
The third law of thermodynamics has to do with entropy. It states that the entropy of a perfectly ordered crystal lattice is zero at the absolute zero temperature.
Let us be reminded that entropy is the degree is disorderliness in a system. Hence, atoms of a crystal lattice stop moving as the system approaches absolute zero, the entropy also tends to a constant value.
This clearly shows that the crystalline structure of a solid material determines the degree of entropy of the solid.
Both protons and neutrons (and their anti-particles) froze out:
A fruit and oatmeal bar contains 142 nutritional calories. Convert this energy to calories
Final answer:
142 nutritional calories (Cal) are equal to 142,000 calories (cal) since one nutritional Calorie is equivalent to 1000 scientific calories (cal).
Explanation:
To convert 142 nutritional calories to calories, you need to understand the relationship between the two units. In nutrition, when we say 'calories', we actually mean 'kilocalories' (kcal). One nutritional calorie (with an uppercase C) is equal to one kilocalorie (kcal), and one kilocalorie is equivalent to 1000 calories (with lowercase c).
Therefore, 142 nutritional calories (Cal) are equivalent to 142,000 calories (cal).
The conversion formula is as follows:
142 Cal * 1000 = 142,000 cal
Which halocarbon has the highest boiling point? 2-dichloropropane 2-chloropropane 1-chloropropane 1,2,3-trichloropropane?
Answer:1,2,3-trichloropropane
Explanation:
A sample of O2 occupies a volume of 600 mL. If the pressure exerted on the O2 is tripled with the temperature remaining constant, the new volume of the oxygen is
Calculate the mass of sodium chloride produced when 5.50 moles of sodium reacts in excess chlorine gas
How to make sulfur hexafluoride?
Which class of compounds is responsible for the scents and flavors of many fruits? amides amines ethers esters
Answer: Esters for Plato
Explanation:
A gas sample occupies 3.50 liters of volume at 20.°c. what volume will this gas occupy at 100°c (reported to three significant figures)?
A gas expands from a volume of 2.00L at 36.0oC to a volume of 2.50 L, what is the final temperature, if the pressure is constant?
The final temperature is 45.45 Celcius
Explanation:
The Combined Gas Law:
The combined gas law allows to derive relationships between the variable that undergoes like pressure, temperature and volume.
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
It is given thatpressure is constant so,
[tex]P_1=P_2[/tex]
Hence combined gas law becomes,
[tex]\frac{ V_1}{T_1}=\frac{V_2}{T_2}[/tex]
Substituting the values given in the question,
[tex]\frac{2.00}{36}=\frac{2.50}{T_2}[/tex]
[tex]0.055=\frac{2.50}{T_2}[/tex]
[tex]T_2=\frac{2.50}{0.055}[/tex]
[tex]T_2[/tex]=45.45 C
An electrochemical cell is made up of two half-cells connected by a salt bridge and an external conductor. What is the function of the salt bridge?
Salt bridge is used to maintain the electrical neutrality in a cell as migration of ions from half cell to other half cell occurs to keep the balance in charges. In the absence of the salt bridge, the charges get imbalanced. After that, the cell stops working because ions will collected in both the electrolytes until the potential difference due to ions and potential difference from the reaction is just opposite to each other. Due to this, flow of electrons doesn't takes place and no current will flow.
Therefore, the function of salt bridge is to maintain the electrical neutrality in a cell.
What is the cause of farsightedness?
The cornea is irregular.
The cornea is opaque.
The eyeball is shortened.
The eyeball is elongated.
Answer:
The eyeball is shortened.
Explanation:
Farsightedness, popularly known as difficulty seeing closely, is a common refractive problem, where the image in the eye forms after the retina rather than exactly over the retina, which hinders the brain's ability to process the image correctly. In farsightedness there is no difficulty in seeing objects from afar, but when you get closer, it becomes very difficult to focus on them.
The eyeball works the same way as a dark box: light enters the pupil and forms the image on the retina. The shape of the eye and cornea is perfect for the image to form in the right place (the macula), and then the information is sent to the brain by the optic nerve.
When you have farsightedness, the eyeball is a little shortened or the flatter cornea, so the image ends up forming after the retina, ie the image the retina captures is not correct.
Which of the following describes the strong nuclear force? A. A strong repelling force between protons and electrons B. A strong attractive force between protons and neutrons C. A strong repelling force between protons and neutrons D. A strong attractive force between neutrons and electrons
Answer:
The correct answer is option B.
Explanation:
Strong nuclear force is defined as strong force of an attraction which binds the quarks together to form a cluster of subatomic particles like protons and neutrons in the nucleus. This is the force which keeps the nucleus intact.
So, we can say that is an strong attractive force between the proton and neutron.
Answer:
B. A strong attractive force between protons and neutrons.
Explanation:
Correct answer for APEX quiz.
For the reaction, identify the Lewis acid and the Lewis base.
AlF3 + CH3F → CH3+ + [AlF4]-
Which of the following equations can be used to determine the change in enthalpy of a system?
Which property of gases allows you to smell popcorn when you walk into a movie theater? compressibility of gas particles diffusion definite shape effusion
Determine the molarity of a solution made by dissolving 11.7 g of NaNO3 in water where the final volume of the solution is 250.0 mL.
Answer:
[tex]0.552~M[/tex]
Explanation:
For the calculation of molarity "M" we have start with the molarity equation:
[tex]M=\frac{mol}{L}[/tex]
So, we have to calculate the moles of [tex]NaNO_3[/tex] and the L of [tex]NaNO_3[/tex].
For the calculations of moles we have to use the molar mass of [tex]NaNO_3[/tex].
Na=23 g/mol
N=14 g/mol
O= 16 g/mol
[tex]molar~mass~=~(23*1)+(14*1)+(16*3)=85~g/mol[/tex]
or
[tex]1~mol~NaNO_3=85~g~NaNO_3[/tex]
Now, we can find the moles of [tex]NaNO_3[/tex]:
[tex]11.7~g~NaNO_3*\frac{1~mol~NaNO_3}{85~g~NaNO_3} =0.138~mol~NaNO_3[/tex]
The next step would be the converstion from mL to L:
[tex]250.0~mL~*\frac{1~L}{1000~mL} =~0.25~L\\[/tex]
Finally, we have to plug both values in the molarity equation:
[tex]M=\frac{0.138~mol}{0.25~L}=~0.552~M[/tex]
if 24500 J is applied to 125g of water at 35 C, what will the final temperature of the water be?
If the temperature of a 5 L sample of gas is lowered from 400k to 200k, what will the resulting volume of the gas be?
Question 4 options:
10 L
50 L
2.5 mL
2.5 L
The answer would be 2.5ML
Which of these changes would cause a decrease in the pressure of a contained gas?
what is the key difference between a liquid and a gas?
Answer :
The key differences between a liquid and the a gas is,
Shape and volume :A liquid has no fixed shape but it has a volume.
A gas has neither a fixed shape nor a volume.
Inter-molecular space :A liquid has more inter-molecular space between the molecules.
A gas has larger inter-molecular space between the molecules as compared to the liquids.
Inter-molecular attraction :A liquid has some Inter-molecular attraction between the molecules because of the low Inter-molecular spacing between the molecules.
A gas has very low or minimum Inter-molecular attraction between the molecules because of the larger Inter-molecular spacing between the molecules.
Fluidity :A liquid flow from the higher to the lower region but a gas flow in all the direction.
Liquids and gases differ from each other in the following ways:
1. Intermolecular forces
2. Motion of particles
3. Direction of flow
4. Compressibility
Further Explanation:
Matter can mainly exist in three physical states. These are solid, liquid and gas.
Solid
It is that state of matter that has a definite shape and volume. These have a regular arrangement of its constituent particles. These have the strongest intermolecular forces between their constituent particles and therefore the motion of particles in solid is almost negligible. Table salt, wood, and diamond are some examples of solids.
Liquid
The state of matter with a definite volume but no particular shape is called liquid. The intermolecular forces in the liquids are weaker than that in solids and therefore the motion of particles in liquids is more as compared to that in solids. Milk, water, and bromine are some examples of liquids.
Gas
This state of matter has neither a definite shape nor a definite volume. These have a disordered arrangement of its constituent particles. These have the weakest intermolecular forces between their constituent particles and therefore the motion of particles in a gas is the highest among all states of matter. Nitrogen, hydrogen and carbon dioxide are some examples of gases.
Liquids have a definite volume but gases occupy the volume of the container in which these are kept.
Liquids have stronger intermolecular forces as compared to that of gases so the motion of gas particles is more than that of liquid particles.
Liquids are incompressible whereas gases are highly compressible in nature.
The flow of liquid takes place from higher to lower level while gases can move randomly in all directions.
Learn more:
1. Which sample is a pure substance? https://brainly.com/question/2227438
2. Which is a characteristic of a mixture? https://brainly.com/question/1917079
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Matter in our surroundings
Keywords: liquid, gas, solid, states of matter, intermolecular forces, shape, volume, matter, strong, weakest, motion of particles.
When 2 mol of solid magnesium mg combines with 1 mole of oxygen gas 2 mol of solid magnesium oxide is formed and 1204 kj of heat is released write the thermochemical equation for the combustion reaction?
The thermochemical equation for the combustion reaction of magnesium with oxygen is:
[tex]\[ 2 \text{Mg}(s) + \text{O}_2(g) \rightarrow 2 \text{MgO}(s) \quad \Delta H = -1204 \text{ kJ} \][/tex]
The given reaction is the combustion of magnesium (Mg) with oxygen (O2) to form magnesium oxide (MgO). According to the stoichiometry provided in the question, 2 moles of solid magnesium react with 1 mole of oxygen gas to produce 2 moles of solid magnesium oxide. Along with the formation of products, 1204 kJ of heat is released, indicating that the reaction is exothermic.
In a thermochemical equation, the reactants are written on the left side, and the products are written on the right side, separated by an arrow that points towards the products. The coefficients in the equation (the numbers in front of the chemical formulas) represent the moles of each substance involved in the reaction. In this case, the coefficients are 2 for magnesium, 1 for oxygen, and 2 for magnesium oxide, as given in the question.
The enthalpy change [tex](\(\Delta H\))[/tex] for the reaction is included at the end of the equation to indicate the amount of heat absorbed or released during the reaction. Since the reaction releases heat, the enthalpy change is negative, and it is equal to -1204 kJ for the given reaction. This negative sign indicates that the system releases energy to the surroundings.
Therefore, the complete thermochemical equation, which includes the stoichiometric coefficients and the enthalpy change, is written as:
[tex]\[ 2 \text{Mg}(s) + \text{O}_2(g) \rightarrow 2 \text{MgO}(s) \quad \Delta H = -1204 \text{ kJ} \][/tex]
This equation accurately represents the combustion reaction of magnesium with oxygen, both stoichiometrically and thermochemically.
When a nucleus undergoes nuclear decay by gamma rays the atomic number of the element?
When a nucleus undergoes nuclear decay by gamma rays the atomic number of the element remains unchanged
When a nucleus undergoes nuclear decay by gamma rays, the atomic number of the element remains unchanged. This type of decay involves the emission of high-energy gamma ray photons, which reduces the nucleus's energy state but does not alter the number of protons or neutrons.
For instance, an isotope in an excited state, such as technetium-99m, undergoes gamma decay to release a gamma photon and becomes technetium-99, but both have the same atomic number of 43.
A 25.0 ml sample of 0.105 m hcl was titrated with 31.5 ml of naoh. what is the concentration of the naoh?
The concentration of the NaOH: 0.083 M
Further explanationTitration is a procedure for determining the concentration of a solution by reacting with another solution which is known to be concentrated (usually a standard solution). Determination of the endpoint / equivalence point of the reaction can use indicators according to the appropriate pH range
Titrations can be distinguished including acid-base titration, depositional titration, and redox titration. An acid-base titration is the principle of neutralization of acids and bases is used.
An acid-base titration there will be a change in the pH of the solution.
From this pH change a Titration Curve can be made which is a function of acid / base volume and pH of the solution
Acid-base titration formula
Ma Va. na = Mb. Vb. nbMa, Mb = acid base concentration
Va, Vb = acid base volume
na, nb = acid base valence
Neutralization Reaction:
NaOH + HCl ⇒ NaCl + H₂O
25.0 ml, 0.105 M HCl was titrated with 31.5 ml of NaOH
Acid-base titration formula
Ma Va. na = Mb. Vb. nb
a = HCl, b = NaOH (both have valence 1)
0.105 M. 25 = Mb. 31.5. 1
[tex]\rm Mb = \dfrac {0.105 \times 25} {31.5} \\\\ Mb = \boxed {\bold {0.083 \: M}}[/tex]
Learn morethe best tool to find the volume of that she needs to neutralize the acid
https://brainly.com/question/1538449
Determine the endpoint of the titration.
https://brainly.com/question/11855003
acid-base
https://brainly.com/question/2860255
Identify the acids and the bases
https://brainly.com/question/12308171
endpoint titration
https://brainly.com/question/1306155
The ratios of volumes of the gaseous reactants and products in a chemical reaction at constant temperature and pressure can be determined from the
Electromagnetic waves, such as visible light, travel in a multitude of orientations. A substance that filters the light so that it only passes through in one plane works somewhat like a fence that allows only some light to pass through. This is the principle of -
A. refraction.
B. diffraction.
C. polarization.
D. interference.