Answer:
O it's not
Explanation:
Have a great day!
What is the enthalpy of reaction for the decomposition of calcium carbonate? CaCO3(s) Right arrow. CaO(s) CO2(g) kJ.
The enthalpy of reaction for the decomposition of calcium carbonate is 177.4 KJ/mole .
We know that the enthalpy of reaction can be obtained from the enthalpy of formation of the reactants and that of the products using the formula;
ΔHrxn = ΔHf (products) - ΔHf (reactants)
The heat of formation of the species are as follows;
ΔHf (CaCO3(s)) = −1206.9 KJ/mol
ΔHf (CaO(s)) = - 636 KJ/mole
ΔHf (CO2(g)) = -393.5 KJ/mole
ΔHrxn = [( -393.5 KJ/mole ) + ( - 636 KJ/mole)] - [ −1206.9 KJ/mol]
ΔHrxn = 177.4 KJ/mole
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Answer:
First one is 656.3 and second is endothermic.
Explanation:
Edge Thermochemical Equations assignment
which statement describes how the binary ionic compound cacl2 is named?
I need help ASAP my final 20 points!!!
What are the compounds that you can find in mayonnaise
HEY!
Mayonnaise is an oil in water (O/W) emulsion; ingre- dients are primarily vegetable oil, egg yolk, sodium chloride, water and vinegar. Its relative stability towards microbial spoil- age has been attributed to the high salt content (in the water phase) and low pH, due to the vinegar.
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carryonlearing
what is the mass of 3.0 x x times 10^23 atoms of neon?
Answer:
10.09 grams
Explanation:
First you need to know the number of moles you are dealing with.
If you know that each mole has 6.022x10²³ of something (in this case of atoms), you can divide 3x10²³ atoms of neons by 6.022x10²³ to obtain the number of moles.
You have 0.5 moles of Neon, so then by the periodic table, you see that the molar mass of neon is 20.18g/mol, so by each mole you have 20.18 grams of neon. Multiply 20.18 grams by 0.5 moles and you got 10.09 grams of Neon
what was johann dobereiner contribution to the periodic table
Answer:
he introduced triads of similar chemical properties in periodic table.
Explanation:
answer this bs for me pls
Answer:
B.chlorine ,Cl2 is the one
Estimate the pressure of 16.25 moles of methane on a 10l container at 300k. Round to the nearest atmosphere
Answer:
The pressure of 16.25 moles of methane = 40 atm
Explanation: there you go
carbon dioxide fire extinguishers are designed for which types of fuels
Answer:
Carbon Dioxide is a non-flammable gas that extinguishes fire by displacing oxygen
CO2s are designed for Class B and C (flammable liquid and electrical) fires only.
HELP ME PLEASE HURRY
The characteristics of two different types of reactions are shown below:
Reaction A: Electrons are gained by the atoms of an element.
Reaction B: Protons are lost by the atom of an element.
Which statement is true about the atoms of the elements that participate in the two reactions?
Their identity changes in both Reaction A and Reaction B.
Their identity changes in Reaction A but not in Reaction B.
Their identity changes in Reaction B but not in Reaction A.
Their identity remains the same in both Reaction A and Reaction B.
Answer:
D is correct
Explanation:
Answer:
A
Explanation:
Electrons are gained by the atoms. There is no change in the nucleus of the atom and the number of protons remains identical.
__H2 + __SO2 —> __H2S + __H2O identify the proper coefficients
a side reaction occurs when acid is added to the system. which species reacts with the acid?
A side reaction occurs when acid is added to the system, so the species reacts with the acid is base.
What are acids?Acids are those species which have a pH range in between 0 to 7, generally acids are present with hydrogen atom in their molecular formula.
If in any reaction after adding the acid, side reaction wiull occur then in this condition base will reacts with the acid as it has the opposite behavior as of acid and formation of salt & water molecules takes plavce.
Hence the needed species is base.
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Select the three hypotheses that explain why being born in the United States leads to a higher chance of developing allergies
- The weather patterns in the United States bring more allergens compared to other countries
- cultural practices may play a part because some cultural foods have different anti-allergenic properties
- other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.
- children in the United States are taught to believe in allergens, but really allergens don’t really exist.
- The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.
The three hypotheses that explain why being born in the United States
leads to a higher chance of developing allergies include the following:
The weather patterns in the United States bring more allergens compared to other countries.Other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.Allergies are caused by a host of factors such as :
ClimateDietImmune systemThese factors is the reason why the chosen hypotheses are the most
appropriate.
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what is actually chemistry
Answer:
Chemistry is the branch of science that deals with the properties, composition, and structure of elements and compounds, how they can change, and the energy that is released or absorbed when they change.
Answer:
Well my teacher said a more complex way he said chemistry is the science that deals with the properties, composition, and structure of substances.
Explanation:
True or false? The empirical formula of a compound is the simplest formula that shows the numerical relationship of the elements in the compound.
Answer:
True
Explanation:
the empirical formula usually shows us the atoms' symbols and then how much of them are present in this certain compound. For example there is H2O
4. If 100.0 g of water is cooled from 25.3°C to 16.9°C, what quantity of
energy has been transferred from the water?
Answer:
Dived the numbers by each other
Explanation:
25.3/19.9
Is a change in color when combining two substances normally a sign of a chemical change or a physical change?
Answer:
Change in colour is a chemical change.
Explanation:
Because when two substances combine chemically, they create (a) new substance(s) that have/has different molecular structures from the parent substances, thus mostly likely absorb and reflect light in different ways.
So if you take an egg and cook it, is it still a baby chicken?
When the egg first forms it's only one cell, and is fertilized as it moves down the oviduct to be laid
__________________________________________________________
this point it's technically an embryo : though it doesn't look like a baby chick
___________________________________________________________
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The more impressive the tail of a male peacock, the higher its chances of finding a mate. Female peacocks choose mates based on the color of the feathers and the overall physical prowess of the animal. However, a genetic mutation called leucism can produce a peacock with only white feathers. This mutation causes the inability of pigment to be deposited into their feathers which results in a white appearance. What would you infer to be the fitness of the white peacock? Choose ALL that apply.
A) The females will equally choose the brightly colored and white peacocks as mates.
B) White peacocks are highly prized, thought to symbolize purity, eternity, and unconditional love, making them desirable mates.
C) If females choose the brightest males as partners, the ones without the impressive tails will be less likely to mate and reproduce.
D) White peacocks are highly prized, thought to symbolize purity, eternity, and unconditional love, causing them to be selectively bred for their unique trait.
E) The peacocks with colored tails will be picked over the white peacocks as mates, causing the peacocks with the white mutation to die out of the population over time
Leucism is a genetic mutation caused by an alteration of a nucleotide. The less brightly colored tails of the peacock will have less chance to mate.
What is selection?Selection is the natural process in which the organism with better trait quality is preferred and selected over another species. They are fit to survive in an altered condition.
The genetic mutation can lead to speciation and selection of the fittest organisms. The type of behavior selection results in the preference of the partners based on the mating and reproducing capabilities.
Therefore, option C. the peacock without impressive tails will be less likely to mate and reproduce.
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Why does atomic radii decrease as you move from the left to right across the period
Answer:
This is because, within a period or family of elements, all electrons are added to the same shell.
When we move from left to right across the periodic table, we can see that the atomic radii keeps decreasing. This is because, as you move from left to right, the nucleus gains protons. The atomic number increases and hence the valence electron will feel more attracted towards the nucleus & the atomic radii will decrease.
[tex]\mathbb{MIREU}[/tex]
a 7.221 g sample of a compound contains 1.990 g carbon, 2.341 g hydrogen, and the rest is oxygen. Determine the
percent composition of the compound
Answer:
17.19%
Explanation:
mass of oxygen = 7.221 - (1.990 + 2.341)
= 2.890g
Empirical formula of the compound
For carbon,
1.990/12 = 0.1658
For hydrogen,
2.341/1 = 2.341
For oxygen,
2.890/16 = 0.1806
0.1658 ÷ 0.1658 = 1
2.341 ÷ 0.1658 = 14.11
0.1806 ÷ 0.1658 = 1.089
Empirical formula of the compound= CH14O
Molar mass= (1×12) + (14×1) + (1×16)
= 12+14+16
= 42g/mol
percentage composition= 7.221/42 × 100
= 17.19%
225 million km to seconds
Answer:
You can't convert km to seconds because they are different units.
Here's the question ~
Heat treatment of muscular pain involves radiation of wavelength of about 900 nm (nm = 10-⁹ m). which spectral line of H - atom is suitable for this purpose ?
[ RH = 1 × 10⁵ cm-¹ ]
[ h = 6.6 × 10-³⁴ Js ]
[ c = 3 × 10⁸ m/s ]
Thanks for Answering !
Using the Rydberg formula, the spectral line of H - atom is suitable for this purpose is Paschen, ∞ → 3.
Using the Rydberg formula;1/λ = RH(1/nf^2 - 1/ni^2)
Given that;
λ = wavelength
RH = Rydberg constant
nf = final state
ni = initial state
When final state = 3 and initial state = ∞Then;
1/λ = 1 × 10^7 m-1 (1/3^2 - 1/ ∞^2)
1/λ = 1 × 10^7 m-1 (1/3^2 )
λ = 900 nm
Hence, the correct answer is Paschen, ∞ → 3
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why is it impossible to have an undiscovered element that would fit between sodium and magnesuim
Answer:
Sodium has 11 protons and Magnesium has 12. The way that the periodic table is set up doesn't allow for any elements to be in between. The element would have to have 11.5 protons, which is impossible
Structure of periodic table is designed in a way that successive elements have difference of 1 electron and proton as sodium and magnesium have 11 and 12 protons respectively there is no space for any other element.
What is periodic table?Periodic table is a tabular arrangement of elements in the form of a table. In the periodic table, elements are arranged according to the modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.
It is called as periodic because properties repeat after regular intervals of atomic numbers . It is a tabular arrangement consisting of seven horizontal rows called periods and eighteen vertical columns called groups.
Elements present in the same group have same number of valence electrons and hence have similar properties while elements present in the same period show gradual variation in properties due to addition of one electron for each successive element in a period.
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Melting gold with other metals makes 10 karat gold. Which term best describes 10 karat gold
The 10 karat of gold formed by melting gold with other metals is described as homogeneous mixture.
A pure substance is a substance that is made up of only one kind of particle. This type of substance consist of only one element.
A heterogeneous substance is a type of substance that is made up two or more substances existing in different phases.
A homogeneous substance is a type of substance that is made up of two or more substances evenly mixed. This type of substance exist only in one phase.
Thus, the 10 karat of gold formed by melting gold with other metals is described as homogeneous mixture.
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Answer:
homogeneous mixture
Explanation:
pls help :)))))))pop
Answer:
c-a-b
Explanation:
Please helppp asapppp due soon ignore the answers i put in their wrong
Which shows the weight of an atom?
atomic mass
atomic number
chemical symbol
none of the above
Answer:
The atomic mass
Explanation:
Answer: atomic mass
Who thought fire was one of four elements?
O A. Aristotle
O B. Marie Curie
O C. John Dalton
O D. Robert Boyle
Answer:
D Robert Boyle
Explanation:
Look at the diagram of metallic bonding. The light blue area represents a sea of... what?
Answer:
try elcetrons
Explanation:
if not then i'm sorry
The light blue area represents electrons.
What is an electron?
An electron is a negatively charged subatomic particle. It can be either free (not attached to any atom) or bound to the nucleus of an atom. Electrons in atoms exist in spherical shells of various radii, representing energy levels. The larger the spherical shell, the higher the energy contained in the electron.
What is the role of electrons?
Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions.
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