Can anyone explain this to me?

Can Anyone Explain This To Me?

Answers

Answer 1
The answer is D, the definition of standard enthalpy of formation is as follows: when one mole of a substance in the standard state (1 atm of pressure and 298.15 K) is formed from its pure elements. The last two words being especially important to this question. We would rule out A, B and C all because the product is formed from a mixture of an element and a compound and not just of elements. In other questions the reactants may all be in elemental form so you must look at the products being one mole or the reactants not being in their standard state.

Related Questions

An element has atomic number 10 and an atomic mass of 20. How many neutrons are in the atom of this element?
OA.
10
OB.
20
O C.
30
D. 0
O E. 200

Answers

10

subtract the atomic mass from the atomic number

describes the
unbalanced attractive force
toward the interior of the liquid
that molecules experience at the
air-liquid interface.
A. Vapor pressure
B. Surface tension
D. Condensation
C. Boiling point

Answers

Answer: B. Surface Tension

Explanation:

It is the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.

Which of the following is an example of an exothermic reaction?
A. Thermal decomposition
B. Ammonium nitrate and water C. Photosynthesis
D. Respiration​

Answers

D but I’m not to sure about it

Exothermic reactions release heat when the reactants produce products. The process of respiration is an exothermic reaction as it releases heat. Thus, option D is correct.

What is an exothermic reaction?

An exothermic is a type of reaction that involves the release of heat during the reaction through product formation. The respiration reaction is exothermic as it involves the breakdown of oxygen and glucose into energy.

Thermal decomposition is an endothermic reaction as it requires energy for completion. Similarly, photosynthesis and reaction between ammonium nitrate and water are endothermic reactions as they also require energy from the external source.

Therefore, respiration is an exothermic reaction.

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Which lists the waves in order of wavelength, from longest to shortest?
A) X-rays, infrared, radio waves
B) infrared, visible light, gamma rays
C) ultraviolet, microwaves, visible light
D) radio waves, gamma rays, visible light

Answers

Answer:

B

Explanation:

gamma rays have the shortest wave length

Infrared, visible light and gamma rays are lists of the waves in order of wavelength, from longest to shortest. Hence, option B is correct.

What is wavelength?

Wavelength is the distance between identical points (adjacent crests) in the adjacent cycles of a waveform signal propagated in space or along a wire.

The electromagnetic spectrum includes, from longest wavelength to shortest: radio waves, microwaves, infrared, optical, ultraviolet, X-rays, and gamma-rays.

Hence, option B is correct.

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I NEED THESE ASAP PLEASE!!!! I WILL MARK A BRAINLIEST...







Magnesium and Chlorine are chemically bonded. Which type of bond holds them
together?

ionic

covalent

neither

Answers

Answer:

The answer should be Ionic

Explanation:

prove me wrong

Ironic I believe


Explanation:

Question 2
Name the following compound:
N_Bro
O Tetranitrogen Nonabromide
O Quadranitrogen Nonabromide
O Nitrogen Bromide

Answers

Answer:

Tetranitrogen Nanobromide

Which substance is the precipitate?

Answers

Answer:

In chemistry, a precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates can form when two soluble salts react in solution to form one or more insoluble products.

Explanation: Hope this helps! :>

Which of the following would increase the intensity of the tornado?



a. decrease in wind speed

b. decrease in condensation

c. increased rate of evaporation

d. increase of cold air

Answers

Answer:

c. increased rate of evaporation

Explanation: Tornado strength is affected by many factors including wind speed, size, where the tornado forms geographically, and duration of the tornado. Additionally, conditions for a supercell storm usually intensify the strength of tornadoes such as humidity, atmospheric instability, lift, and vertical wind shear.

is 2Sb+3L2-> 2SbL3 endothermic or exothermic?

Answers

Answer:

try working out the bond enthalpies for both sides of the equation :)

Explanation:


Why are the transition metals able to show different properties like varying color and paramagnetism ?

Answers

Answer:

Colors of transition metal compounds are due to two types of electronic transitions. Due to the presence of unpaired d electrons, transition metals can form paramagnetic compounds. Transition metals are conductors of electricity, possess high density and high melting and boiling points.

Explanation:

The  transition metals are  able to show different properties like varying color and paramagnetism due to presence of unpaired d-electrons.

What are transition metals?

The transition metals are defined as the elements  in which atoms are present whose d-sub-shell is partially filled .Due to which they give rise to cations with an incomplete d-sub-shell.

They are also defined as the elements which are present in the d-block of the periodic table, which includes groups from three to twelve.These elements are called transition elements as they show a transition between highly electro-positive group 1 and highly electro-negative group 17 elements.

They have characteristic properties due to which they can exist in variable oxidation states , form colored complexes and have catalytic properties as well.These elements are all technologically very important.

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Write a short note on LAN? Also write down its advantages and disadvantages of LAN?​

Answers

Area network is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus, or office building.

The advantages of local area network are:

• you can share resources
•you can share your software applications
• you can have easy and cheap communication
• you have centralized data
• you have data security
•you have Internet sharing

The disadvantages is a local area network are:

• high set up cost
• local area network administrators can see and check personal data files of each and every user
• Data security threats
• maintenance jobs
• covers limited areas

What are Oxygens important uses (and why)?

Answers

Answer:

Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.

Explanation:

Oxygen is used to degrade hydrocarbon compounds, which are broken apart by heating them. This is used to create combustion that usually liberates water and carbon dioxide, but can also produce the hydrocarbons acetylene, propylene and ethylene. Oxygen is used in sewage-treatment and water-purification plants.

(HELP FAST)Which of the following always changes when a substance undergoes a
chemical change?

Answers

arrangement of atoms composing the substance (C) should be the correct answer. Color doesn’t always change, along with mass and the state of matter doesn’t always occur with a chemical reaction

when the white part is on the left the moon is.??​

Answers

Answer:

Last Quarter also called Third Quarter.

Explanation:

NEED HELP!!!
Which word best describes a form of energy associated with molecules in motion and heat?
Thermal energy
Kinetic energy
Vaporization
Condensation

Answers

Thermal, think thermometer and heat.

Guys please help me


What happens when the number of electrons and protons inside of or atenie equel?

Answers

Answer:

When the number of electrons does not equal the number of protons, the atom is ionized and then they are no longer atoms, they are known as ion(s).

how is mechanical energy related to potential and kinetic energy

Answers

Answer:

Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy (stored energy of position). A moving car possesses mechanical energy due to its motion (kinetic energy).

Explanation:

The particles are in a fixed position. What state of matter is this?

Answers

Answer:

The state of matter is solid

Explanation:

What unit is mass generally measured in

Answers

Answer:

kilograms

Explanation:

hope this helps, pls mark brainliest :D

Answer:kilogram

Explanation:

I got the smarts

what are the coefficients that will balance the skeleton equation​

Answers

Answer:

When the following equation is balanced, what is the coefficient for HCl? Mg(s) + HCl(aq) -> MgCl2(aq) + H2(g) . 2. What are the coefficients that will balance the skeleton equation below? AlCl3 + NaOH -> Al(OH)3 + NaCl.

NEED HELP?!! Whats the answer

Answers

The answer in letter D

list down some examples of solutions that we need to prepare/make in the form of unsaturated and saturated solution​

Answers

Answer:

1)Carbonated water is saturated with carbon, hence it gives off carbon through bubbles.

2)Adding sugar to water until it no longer dissolves creates a saturated solution.

3)Continuing to dissolve salt in water until it will no longer dissolve creates a saturated solution.

An unsaturated tea and sugar solution would be one into which you could add more sugar and have the sugar still dissolve

Help? i need to finish my assignment :>

Answers

Answer:

B 2

Explanation:

I checked it and it’s right hope this helps!!

can someone explain this to me?​

Answers

Answer:it says how to make an atom stable like ion if the atom is metal then it will lose the atom to be full outer shell and if it is non metal it will gain.

second thing there is also covalent bond which share electron with other atomto be full outer shell

hope this help!!

) Calculate the Gibbs energy change for the formation of propane at 298K.Given that ∆H for propane is -103.85KJ/mol.∆S for the reaction is - 269.74KJ/mol.

Answers

Answer:

ΔG = 80,278.67 J/mol

Explanation:

Given:

∆H = - 103.85KJ/mol

∆S = - 269.74KJ/mol

T= 298 K

The Gibbs energy change (ΔG) is calculated as follows:

ΔG = ΔH - TΔS

ΔG = (-103.85KJ/mol)-298K(- 269.74KJ/mol)

ΔG = (-103.85KJ/mol) - (-80,382.52 J/mol)

ΔG = 80,278.67 J/mol

Calculate the molarity of a solution prepared by dissolving 2.50 mol of KCl into 2.00 L of solution.
________ M​

Answers

Answer:

1.25 M

Explanation:

The molarity is found dividing the moles of solute by the litres of solution.

2.50 mol ÷ 2 L = 1.25 M

The concentration terms are molality, normality and mole fraction. Molarity can be used to find out the ionic strength of any solution. Therefore, the molarity of  a solution prepared by dissolving 2.50mol of KCl into 2.00 L of solution is 1.25 M.

What is molarity?

Molarity can be calculated by dividing number of moles of solute by volume of solution in liter. Molarity is affected by temperature. Its unit is mole/liter. It measure the concentration of any solute in a solution.

Mathematically,

Molarity= number of moles of solute/volume of solution in liter

number of moles of solute KCl= 2.50 mol

volume of solution in litre = 2.00 L

substituting all the given values in the above equation, we get

Molarity= 2.50 mol ÷ 2 L

Molarity =  1.25 M

Therefore, the molarity of  a solution prepared by dissolving 2.50mol of KCl into 2.00 L of solution is  1.25 M.

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A student adds different amounts of ice to four samples of water and records the change in temperature after 30 minutes. What is the independent variable in this investigation?

Answers

Answer:

Amount of ice

Explanation:

When we talk about independent variable, we mean that variable in an experiment that is manipulated and its effect on the dependent variable is measured.

In this case, the amount of ice in each water sample determines the temperature of each sample. Hence the amount of ice is the independent variable.

Answer:

ice cubes added

Explanation:

A base used in baking cake is

Answers

Answer:

sodium bicarbonate, potassium bicarbonate and ammonium bicarbonate are the most commonly used bases.

Identify each type of reaction shown below:

Answers

Answer:

See explanation

Explanation:

1. Decomposition= when one compound or substance is separated into 2 elements.

2. Single displacement: b is switched with c

3. double displacement: when 2 reactants form 2 different products

4. Anh measured the temperature of a pond near his house. Before he left for school, the water in the
pond was 18°C. When he came home from school, the temperature of the pond was higher than it
was in the morning. What happened to the water molecules while he was at school?

Answers

The water molecules must have gained more thermal energy while Anh was away from the house.

An increase in the temperature of a body means that the body has gained more energy in the form of heat, also known as thermal energy.

The thermal energy represents the characteristic of a body responsible for its temperature.

An increase in the temperature of the water molecules increases their kinetic energy and, thus, makes the water molecules move around faster than before.

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