Answer:
This equation essentially states that the standard enthalpy change of formation is equal to the sum of the standard enthalpies of formation of the products minus the sum of the standard enthalpies of formation of the reactants. and the standard enthalpy of formation values: ΔH fo[A] = 433 KJ/mol.
Explanation:
Hope this helps.
Which of these element is NOT an alkali metal? Na Rb H cs
Answer: Hydrogen-H
Explanation: Hydrogen is a gas, the most abundant element in the universe and the simplest of them all
Based on location in the periodic table, which element has chemical properties that are most similar to iodine
xenon (Xe)
calcium (Ca)
Selenium (Se)
fluorine (F)
Answer:fluorine
Explanation:
Based on location in the periodic table, fluorine (F) has chemical properties that are most similar to iodine.
In the periodic table, elements are classified in groups and periods. The elements in the same group are chemically similar and they have the same number of valence electrons. Elements in the same period have the same highest energy level.
Hence, when looking for an element that is most chemically similar to iodine, we have to consider the element that is in the same group with iodine.
Both fluorine are iodine are both in group 17 hence, fluorine is most chemically similar to iodine.
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1. Calculate the energy in joules of a photon of electromagnetic radiation whose frequency is 2.76×1014 s−1 .
Express your answer with the appropriate units.
2. Calculate the energy in joules of a photon of radiation whose wavelength is 418 nm
Express your answer with the appropriate units.
3. What wavelength (in meters) of radiation has photons of energy 6.05×10−19 J ?
Express your answer with the appropriate units.
Answer: 41.5
Explanation:
three moles of sodium carbonate are mixed with two moles of lead nitrate in aqueous solution, leading to formation of a solid precipitate. how many moles of spectator ions remain in solution, assuming 100% yield of the precipitate?
There are 4 moles of spectator ions that remain in solution.
The equation of the reaction is;
Na2CO3(aq) + Pb(NO3)2(aq) -------> PbCO3(s) + 2NaNO3(aq)
We have to determine the limiting reactant. This is the reactant that yields the least amount of product. Note that the spectator ions are Na^+ and NO3^- that form NaNO3.
For Na2CO3
1 mole of Na2CO3 yields 2 moles of NaNO3
3 moles of Na2CO3 yields 3 × 2/1 = 6 moles of NaNO3
For Pb(NO3)2
1 mole of Pb(NO3)2 yields 2 moles of NaNO3
2 moles of Pb(NO3)2 yields 2 × 2/1 = 4 moles of NaNO3
We can see that Pb(NO3)2 is the limiting reactant.
Since [NaNO3] = [Na^+] = [NO3^-], it follows that there are 4 moles of spectator ions that remain in solution.
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Pots and pans that are used for cooking are often
made of copper, aluminum, and iron. Explain how metallic bonding makes these
metals suitable for this use.
Cooking materials are made of copper, aluminum, and iron because they contain free, mobile electrons owing to the metallic bond.
Metallic bonding involves a sea of electrons that is bonded to metal cations by electrostatic attraction. The electrons in the metallic bond are free to move around the material.
Because there are free electrons, when the material is heated, the electrons receive energy and move faster, this energy spreads throughout the material by conduction.
Hence, good conductors of heat such as copper, aluminum, and iron are used for cooking materials.
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What is the correct name for Fe203?
A Iron(V) oxide
B Iron(III) oxide
C Iron(I) oxide
D Iron(II) oxide
Answer:
The answer would be B.
Explanation:
what are the units for the rate constant of a first-order reaction?
Explanation:
the units for the rate constant of a first-order reaction is :
[tex] = {s}^{ - 1} [/tex]
what happens when a liquid becomes a gas
Answer:
When a liquid changes to gas, the particles absorb heat energy and they start vibrating faster and distance between them increases. On constant vibration, intermolecular forces decrease and particles start moving away from each other and change to gas.
an immiscible mixture that is not composed oil and water
Answer:
"like-dissolves-like"
Any polarized molecule will not be soluble in a mixture of non-polarized molecules. Also, Acids and Bases mix with one another but not into neutral compounds. Organic molecules also do not mix with non-organic or aqueous solutions (like those without neutral pH)
Explanation:
water resists changing its temperature because it has a high specific heat. true or false?
Answer:
true
Explanation:
Which is the best definition of air pressure?
A.the amount of water vapor in the air.
B.the weight of the air pressing on everything in the environment
C.the amount of precipitation in a certain area
D.the type of clouds in the atmosphere
help me with this:((
1. a
2. a
3. b
4. b
5. c
6. a
7. c
how many moles of HNO3 would be formed from 1.0 mole of NO2
classify these diatomic molecules as diamagnetic or paramagnetic.
Dissolving and melting are similar because both
A. result in a change in mass.
B. are kinds of physical change.
C. involve even mixing of substances.
D. result in new substances being formed.
Answer is B are kinds of physical change.
How do you know where something fits on the electromagnetic spectrum? I currently have the Hz but do I need to convert that into something else?
Find the mass of iron that has volume of 111 ml.
Answer:8
842.46 or to the next whole number
Explanation:
just multiply the mass of iron with the volume mL you have.
The mass of the iron whose volume and density are 111 ml and 7.847 g/cm³ respectively is 871.01 grams.
Which term is equivalent to product of density and volume?
The product of density and volume of a substance represents its mass. Mathematically -
M = V x ρ
where -
ρ - density
M - mass
V - volume
Given is iron in liquid form. It occupies a total volume of 111 ml.
The mass of liquid iron can be calculated using -
M = V x ρ
Volume of iron [V] = 111 ml = 111 cm³.
Density of iron [ρ] = 7.847 g/cm³
Therefore, we can write -
M = 7.847 x 111
M = 871.01 grams
Therefore, the mass of the iron whose volume and density are 111 ml and 7.847 g/cm³ respectively is 871.01 grams.
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coal mining environmental impact
Explain what impact coal mining has and what it affects
CAN SOMEONE PLS HELP THANK U
Answer:
There are significant environmental impacts associated with coal mining and use. It could require the removal of massive amounts of top soil, leading to erosion, loss of habitat and pollution. Coal mining causes acid mine drainage, which causes heavy metals to dissolve and seep into ground and surface water.
Explanation:
how many valence electrons does alkali metals gain or lose
Answer:
Alkali metals have 1 valence electron on their outer shell. They are more stable when they have 8 valence electrons, so they want to lose that valence electron. They do this by bonding with other elements. When they lose their 1 valence electron, they have a full octet and are therefore stable.:
pls help i need the Formula
how can you calculate the number of electrons present in a shell? pls help!!! will give brainliest
Answer:
The maximum number of electrons present in a particular shell is calculated by the formula 2n2, where “n” represents the shell number. For instance, K shell is the first shell and it can hold up to 2(1)2 = 2 electrons. Similarly, L shell is the second shell and it can hold up to 2(2).
I will brainless who can answer this all pleaseeeee
Answer:
I think the answer is yellow or White
Explanation:
because it is the visible light that I know
mask me as brainless
thanks
All alkalis are bases but not all bases are alkalis. True or False?
Answer:
A substance that neutralizes an acid is generally called a base and the basic substances that are soluble in water and alkali and the properties of alkalis are due to these hydroxide ions(OH−). ... - Thus, conclusively it can be said that all alkalis are bases but all bases are not alkali.
Answer:
This is false
Explanation:
it is actually the opposite, all bases don't dissolve in water, but alkali is a base that does dissolve in water. So, alkalis are bases, but not all bases are alkalis
Pinky, message in one of my answers that doesn't have an comment on pls.. i wish i can tlk to u.. but this new system in brainly.. oof
Why is newton's first law of motion considered a law and not a theory?It is an unsupported idea.It is based on multiple observations.It has never been tested.It was validated by a singular experiment.
Answer: B. It is based on multiple observations.
Explanation:
Newton's first law of motion is considered a law and not a theory because it is based on multiple observations.
What is an observation?
Observations are defined as a set of statements or facts which are recorded while conducting an experiment.Observations are made through sensing changes in the variables of the experiment.
It is specifically defined as an act of knowing or recording the changes in the variables of the experiment.Recording observations holds importance as recording observations avoid the experiment to be repeated over and over again.
It is important to note down observations so that the testing of hypothesis is made easier.There are four types of observations .Observations need to be descriptive and must be written in complete sentences and should include all the numerical data of the experiment.
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the elements in the far upper right corner are classified as
distillation could not be used to separate one of the following:
a. rubbing alcohol and water
b. motor oil and brake fluid
c. sand and gold
d. gasoline fractions
i’m not sure but i think it is c
Answer:
It's motor oil and brake fluid
5.
The weight of an object is the force of attraction between the object
and the Earth
TRUE
FALSE
Answer: True
Explanation:
If you’ve seen a baseball game, you’ve probably also experienced the sight of a ball going up and up, until you begin to wonder when it’s going to come down! Yet every time, the ball does fall back to earth. Why? Gravity is an attractive force that exerts a pull between two objects, such as a baseball and the earth.
Knowing an object's position requires which of the following? A. speed B. time C. displacement D. reference point
Knowing an object's position requires the (D) reference point
Reference point is the starting point use to locate another place or object. an object's position depends on reference point.
Position describes the distance and direction from reference point for an object. position of an object's is the location to the reference point.
Displacement is the difference between the initial position and the final position.
Speed is defined as the distance an object travels per unit time.
Time is defined as the duration of an object travels to cover a distance.
so according to all , reference point is needed to determine the position of an object's.
Thus, Knowing an object's position requires the (D) reference point
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which scientist developed the nuclear model of the atom?
Answer:
Earnest Rutherford
Explanation:
From what I beleive, Rutherford had created the nuclear model
Meat or fish spoilage is often due to spoilage bacteria which utilize. to grow in population.
glucose and free amino acids.
glucose
free amino acids
sulfides
Answer:
glucose and amino acids
Explanation:
decide how to supersets these substances? If if is not possible, please write "cannot be separated" on the space provided
Answer: (although the question does not sate whether if you separate them physically or through energy. so i did both)
1. can be separated (When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen)
2. can be separated, but through electrolysis, fiscally moving a crane to generate electricity to separate the molecules
3. Most solid particles, composed of diamagnetic or weak paramagnetic materials, cannot be extracted by a conventional magnetic separator. physically cannot be separated. but through heat yes
4. but there is a catch: doing so requires energy. ... If energy from coal were applied to drive the decomposition reaction, more CO2 would be released than consumed, because no process is perfectly efficient. so it cant be separated physically
5. it can be separated but it needs energy physically cannot be separated.
Explanation: