An endothermic reaction occurs when water and ammonium nitrate are combined. Which of the following statements correctly
describes the energy changes in the reaction?
OA. Energy is released because the reactants have more chemical energy than the products.
OB. Energy is absorbed because the reactants have more chemical energy than the products,
OC. Energy is absorbed because the products have more chemical energy than the reactants.
OD. Energy is released because the products have more chemical energy than the reactants.
Answer:
C.Energy is absorbed because the products have more chemical energy than the reactants.
Explanation:
which describes an attribute of nonrenewable resources
Answer:
atributes of nonrenewable recources are things you cant re use after 1 use like gas
Explanation:
Answer: the answer is b. Are unlimited
Explanation:
Formulate a hypothesis based on something recently observed.
And How could this hypothesis be tested?
Answer:
If garlic repels fleas, then a dog that is given garlic every day will not get fleas. Bacterial growth may be affected by moisture levels in the air. If sugar causes cavities, then people who eat a lot of candy may be more prone to cavities.
Explanation:
What has a larger mass, a mole of oxygen gas or a mole of neon gas?
Answer:
1 mole ozone gas
Explanation:
Since atomicity of Ozone (3) is maximum so, it will contain maximum number of atoms.
State of Matter refers to _______.
Answer:
matter refers to anything that has mass and volume which occupies space
Question 20 0/1 pts What is the frequency of a light wave with the wavelength of 680 nm? 'Reminder: the speed of light is 3.00 X 10 m/s
Answer:
[tex]4.4*10^{14}[/tex]Hz
Explanation:
Which of the following giant covalent structures does not have a high melting and boiling
point?
a) Polythene
b) Graphite
c) Silicon dioxide
d) Diamond
Answer:
Polythene has the lowest melting/boiling point from all the other covalent structures mentioned in this question.
Answer:
Polythene (polyethene according the IUPAC nomenclature.)
Explanation:
Consider the structure of each option:
Polythene: long chains of atoms that are able to rotate along the bonding axis. Graphite: layers of (hexagonal) carbon sheets; each individual sheet is rigid (allows no rotation.) Silicon dioxide: three-dimensional (tetrahedral) network of carbon and oxygen atoms; the entire network very rigid (allows no rotation.)Diamond: three-dimensional (tetrahedral) network of carbon atoms; likewise, the entire tetrahedral network is very rigid.Melting each structure requires overcoming the forces that hold the structure rigid:
In polythene, van der Waal forces hold the chains together and prevents rotations.Deshaping graphite requires bending the layers; doing so would require overcoming the covalent bonds within the hexagonal sheets.In silicon dioxide and diamond, deshaping the tetrahedral network also requires overcoming covalent bonds.Van der Waal forces are much easier to break than covalent bonds.
Hence, the melting point of polythene would be the lowest among the options.
If the temperature changes by 100 K, by how much does it change in degrees Celsius?
A. 0 degrees Celsius
B. 100 degrees Celsius
C. 37 degrees Celsius
D. 273 degrees Celsius
Taking into account the degrees Celsius and Kelvin, if the temperature changes by 100 K, by 100 degrees Celsius it change in degrees Celsius.
A degree Centigrade is a unit of temperature (the physical quantity that reveals the level of heat) whose symbol is °C.
On the other hand, the degree Kelvin, whose symbol is K, is the unit of temperature on the scale created by William Thomson Kelvin, in 1848, based on the degree Celsius, he established his zero point (0) at zero absolute (-273.15 ° C). The figure 0 K is equivalent to the theoretical point where gases have no volume. Absolute zero or 0 K is the point where molecules theoretically stop moving. It is the "perfect" cold.
Considering that zero on the Celsius or degrees centigrade (0 ° C) scale is defined as the equivalent of 273.15 K, the conversion from degrees ° C to K is carried out using the following expression:
T(K)= T(°C) + 273.15 K
In this case, if the temperature changes by 100 K, as it is a change in temperature, the numerical value in K units is the same in ° C units.
Then, the correct answer is option B. if the temperature changes by 100 K, by 100 degrees Celsius it change in degrees Celsius.
Learn more about degrees Celsius and Kelvin:
https://brainly.com/question/2800860?referrer=searchResultsWhich model of the atom is thought to be true?
A. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.
B. The nucleus is made of protons, electrons, and neutrons.
C. Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
D. The nucleus is made of electrons and protons.
Answer:
Hi the answer should be B or 2
Explanation:
Hope this helps!
Hey y’all is these answers correct?
Answer:
ʏᴇs, ɪ ᴛʜɪɴᴋ
Explanation:
TᕼᗩᑎKՏ ᒪOᗪՏ
how many moles are in 8.32 × × times 10^24 molecules of co2?
Answer:
13.8 moles
Explanation:
You know that in a mole you have 6.022x10²³ something in this case of molecules. By knowing that by each mole you have 6.022x10²³ molecules, then you can establish the factor of conversion:
8.32x10²⁴molec of CO2 x 1 mol/6.022x10²³ molec of CO2
You divide 8.32x10²⁴/6.022x10²³ and you get 13.81 moles.
name a metal and non metal which are liquid at normal pressure and temperature
Answer:
metal : Mercury(Hg)
non metal : bromine (Br)
Explanation:
mercury is liquid at room temperature and pressure and the same as bromine
can somebody please help me here ? i wanna make sure of my answer..
Answer:
[Unfortunately] Answer is A
Explanation:
You should know that 'liquid' is a state of matter and aqueous means that there is water present.
-It is mentioned that barium chloride is a solution. So you can cut off the C option.
-Barium sulfate is a salt which means it's a solid, so you can cut off the D option.
We now have A and B as the only options remaining.
-Dilute sulfuric acid is definitely not a liquid because water is present. (dilute indicates that there is a greater proportion of water)
The answer should be A.
what are subatomic particles?
Explanation:
a particle smaller than an atom (e.g., a neutron) or a cluster of such particles (e.g., an alpha particle).
Helppp plzzzz!!!!!!1Asappppp
Answer:
0.178M
Explanation:
The question can immediately be understood as comparing two states.
- The initial state M1 , V1.
- The Final state M2 , V2.
M - Molarity.
V - Volume (in mili liters/ml/ in this case).
The formula is stated as:
M1 * V1 = M2 * V2
Given- Required
M1 = 0.125M V1 = 265ml M2 = ?
V2 = 186ml
Plug these values into the formula above and divide V2 to get M2.rearranged formula - M2 = M1 * V1 / V2 = 0.125M * 265ml / 186ml
= 0.178091397 M ~ ~ 0.178M.
What is the mass of air in room
Answer:
the mass of the air in the room is 4.96512 kg ( in 0°C)
what is a “ medium” in regards to waves ?
how much water will you need to add to your working solution to get to a 100 ml total volume of a 0.03m nacl solution?
Answer:
The solution is made by adding 4.38 g NaCl to a 250-mL volumetric flask. About 100 mL of water are added and when all the NaCl dissolves water is added up ...
PLEASE HELP!!!
ILL MARK AS BRAINIEST AND GIVE YOU 30 POINTS!!!
Answer:
did u get it yet
Explanation:
Knowing that the solubility of a salt at 80°C is 45g/100 g of H,O, calculate the mass of water required for dissolve 250 g of this salt at 80º C.
The mass of water required will be approximately [tex] \bf = 555.6\: g [/tex].
To solve this question, just make a simple rule of three between the amount of salt dissolved at 80ºC and the mass of water:[tex]\qquad[/tex] 45g of salt [tex] \sf \longrightarrow[/tex] 100g of H₂O
[tex]\qquad[/tex] 250g of salt [tex] \sf \longrightarrow[/tex] x g of H₂O
[tex]\qquad[/tex] [tex]\red{\twoheadrightarrow\bf45\times x = 250\times 100}[/tex]
[tex]\qquad[/tex] [tex]\twoheadrightarrow\sf45x=25000[/tex]
[tex]\qquad[/tex] [tex]\twoheadrightarrow\sf x=\cancel{\dfrac{25000}{45}}[/tex]
[tex]\qquad[/tex] [tex]\red{\twoheadrightarrow\bf x = 555.6\:g}[/tex]
Therefore, knowing that the solubility of a salt at 80ºC is 45g/100g of water (H₂O), the mass of water needed to dissolve 250g of this salt at 80ºC will be [tex] \red{\bf = 555.6\: g }[/tex]__________________________________________________
which of the following best describes a single replacement reaction?
two elements combine to form a compound
one element takes the place of another in a compound
two elements switch places in a compound
a compound breaks into separate elements
Answer:
One element takes the place of another in a compound
Explanation:
I just took a test for it and got it right. :)
Hope This Helps :)
why is it hotter in the summer and colder in the winter?
Answer: During the summer, the sun's rays hit the Earth at a steep angle. ... Also, the long daylight hours allow the Earth plenty of time to reach warm temperatures. During the winter, the sun's rays hit the Earth at a shallow angle. These rays are more spread out, which minimizes the amount of energy that hits any given spot.
Pls Help Me (20 Points)
In one to two sentences, explain how to compare the strength of electrostatic forces between molecules in salt water to the strength of electrostatic forces between molecules in freshwater. Include a description of the data to be collected and how that data would allow one to draw conclusions about the relative strengths of the electrostatic forces in the two substances.
Answer:
-Salts are composed of ions that form a tightly packed and ordered network, which is called a crystal lattice, and it is held together by ionic bonds.
Explanation: salts are ionic compounds, which are composed by oppositely charged ions (cations and anions) which are bonded each other by ionic bonds, in an ordered arrangement, often a crystalline solid.
-When a salt is added to a polar solvent like water, the ions interact with the solvent molecules via ion-dipole forces, which overcome the forces originally holding the ions together.
Explanation: the molecules of a polar solvent are dipoles because they have dipolar momentum (a difference in charge due to a electronegativiy difference). When a salt is dissolved in a polar solvent, it dissociates in ions. So, the resulting interactions between these species are ion-dipole forces.
-The ions are then isolated and stabilized in solution via these interactions, and when this occurs for most of the salt compound, it is considered soluble in that solvent.
Explanation: the ions in solution are surrounded by solvent molecules which stabilizes them. A salt which is enterely dissolved in a solvent is soluble in that solvent.
-Due to the nature of the interaction between ions and solvent molecules, a concentration of ions can be dissolved higher in water than in alcohol.
Explanation: water molecules have unique properties that make water an universal solvent. Due to these properties and its polarity, water can dissolve larger quantities of salt than other polar solvents such as alcohol.
The electrostatic force in water without salt is stronger as compared to the water due to the presence of free electrons.
In water hydrogen bonding is present that is the only kind of electrostatic force present in the water. In water containing salt sodium and chloride ions are present which conduct strong electrostatic force. A static meter is ideal for measuring the of liquids. It measures the charge on the liquid. Hence, the electrostatic force in salt water is stronger as compared to the water due to the presence of free electrons.Learn more about electrostatic:
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Part A
Before you design your model village, write down the problems you observed in task 1. What were the largest risks to the community? What happened to the homes?
The largest risks while designing a model to withstand a village include that the model does not mitigate the effects of the tsunami or only mitigates the effects partially, which would cause damages to the homes.
Designing a model to withstand the effect of any natural phenomenon such as an earthquake, fire or tsunami is not an easy task and will require the following cycle:
Designing the model.Testing the model.Making changes or designing a new model.In the case of a model for tsunamis, it is likely the following problems occur:
The model does not protect the houses from tsunamis.The model does not protect the houses completely.This would lead to negative effects such as:
Damages in the houses.Dead or injured people.Destruction of infrastrcture.Note: This question is incomplete because the context is missing; here is the missing part.
Protecting Your Model Village from Tsunamis this task, you will design a model village to withstand the effects of a tsunami.
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How many molecules are present in this formula? 3H2 (SO)4
Molecules are formed when two or more atoms chemically bond together. In 3H₂(SO)₄, three molecules are present.
What are molecules?Molecules are the smallest unit present in any compound and are formed by a group of atoms. A number denoted in front of the chemical species is the coefficient that represents the number of molecules.
The coefficient present in front of the reactant or the product in a chemical reaction gives the number of the molecules present in a compound. As three is denoted in front of the sulphuric acid, hence will be the number of the molecules.
Therefore, there are three molecules present in sulphuric acid.
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what is the equilibrium concentration of co at 1000 k?
Answer: For the reaction, K c = 255 at 1000 K. If a reaction mixture initially contains a CO concentration of 0.1550 M and a Cl 2 concentration of 0.171 M at 1000 K. 1.
Explanation:
what is the molarity of a koh solution if 25.0 ml neutralizes 35.0 ml of a 0.200 m hcl solution?
If 25.0ml neutralizes 35.0 ml of a 0.200M HCl solution, the molarity of KOH solution is 0.28M
The reaction between KOH solution and HCl is written below.
[tex]HCl + KOH \rightarrow KCl + H_2O[/tex]
Volume of KOH, [tex]V_B[/tex] = 25.0 ml
Volume of HCl, [tex]V_A=35.0 ml[/tex]
Molarity of HCl, [tex]C_A=0.200 M[/tex]
Molarity of KOH, [tex]C_B=?[/tex]
Number of moles of HCl, [tex]n_A=1[/tex]
Number of moles of KOH, [tex]n_B=1[/tex]
The mathematical equation for neutralization reaction is:
[tex]\frac{C_AV_A}{C_BV_B} =\frac{n_A}{n_B}[/tex]
Substitute [tex]C_A=0.200 M[/tex], [tex]n_A=1[/tex], [tex]n_B=1[/tex], [tex]V_B[/tex] = 25.0 ml, and [tex]V_A=35.0 ml[/tex] into the equation above in order to solve for [tex]C_B[/tex]
[tex]\frac{0.2 \times 35}{C_B \times 25}=\frac{1}{1} \\\\25C_B=7\\\\C_B=\frac{7}{25} \\\\C_B=0.28M[/tex]
Therefore, the molarity of KOH solution is 0.28M
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Mendeleev's arrangement of the periodic table was in order of increasing ____.
A. atomic number
B. atomic mass
C. neutron number
D. valence electron number
Answer:
B. atomic mass
Explanation:
He arranged the elements into rows in order of increasing mass so that elements with similar properties were in the same column.
When the equation for the reaction represented below is balanced and all coefficients are reduced to lowest whole-number terms, the coefficient for Al(s) is __ Al(s) + __ O2(g) __ Al2O3(s)
This question is asking for the correct balanced reaction, when solid aluminum reacts with gaseous oxygen to form solid aluminum oxide, according to the law of conservation of mass, which demands us to have the same number of atoms of each element on both sides of the equation.
In such a way, we can start by knowing there is one aluminum atom on the left and two on the right whereas there are two oxygen atoms on the left and three on the right side of the equation.
The aforementioned means we must balance oxygen first by putting a 2 on aluminum oxide and a 3 on oxygen in order to cross multiply and obtain six oxygen atoms on both sides of the equation.
Moreover, the 2 on the aluminum oxide makes four aluminum atoms on the right, which means we must put a 4 on the left-handed aluminum in order to get the correct balance, and therefore, write the following balanced equation:
4Al(s) + 3O₂(g) ⇒ 2Al₂O₃(s)
Hence, the coefficient for Al, as asked, is 4.
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https://brainly.com/question/11322377 https://brainly.com/question/7181548How do chemists predict the shapes of molecules?
Due to the repulsion between electrons, valence electrons will be arranged as close to each other as possible.
Due to the attraction between electrons, valence electrons will be arranged as close to each other as possible.
Due to the repulsion between electrons, valence electrons will be arranged as far apart from each other as possible.
Chemists can't predict the shape of molecules, because the attractive forces between valence electrons are unpredictable.
A. Due to the repulsion between electrons, valence electrons will be arranged as close to each other as possible.
The approximate shape of a molecule can often be predicted by using what is called the valence-shell electron-pair repulsion (VSEPR) model.Electrons in bonds and in lone pairs can be thought of as a charge cloud that repels one another and stay as far apart possible, thus causing molecules to assume specific shapes.The shape of a molecule is determined by the location of the nuclei and its electrons.Therefore, the correct option is A.
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