Answer: covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. Covalent bonds form only between atoms of nonmetals. The two atoms that are held together in a covalent bond may be atoms of the same element or different elements.
Explanation:
A gas sample in a balloon contains 4.0 moles of gas at a particular pressure, volume and temperature. If your balloon springs a leak and the volume decreases to 1/2 of the original amount before you can plug the leak, how many moles of gas have you lost (temperature and pressure remain the same)?
Answer:
Explanation:
When volume of gas is V , pressure is P and temperature is T , if n be number of moles of gas
PV / RT = n , R is universal gas constant .
When volume becomes .5 V , pressure P and temperature T
number of moles = Px .5 V / RT = .5 PV / RT = .5 n
Number of moles of gas becomes half .
so 4 moles becomes 2 moles
No of moles lost = 4 - 2 = 2 moles.
6. Choose the best answer.
The definition of consecutive is:
to get in the way of; to try to prevent
facts and information
telling the meaning of
a condition of being complicated; having many parts
following one after another
Answer:
to get in the way of;to try to prevent facts and information
When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2 precipitates, as shown in the netionic equation below. The initial temperature of both solutions is 23.0°C. Assuming that the reaction goes tocompletion, and that the resulting solution has a mass of 100.00 g and a specific heat of 4.18 J/(g ∙°C), calculatethe final temperature of the solution.Ca2+(aq) + 2 F-(aq) → CaF2(s)∆H°=-11.5 kJ
Answer:
23.55°C
Explanation:
Based on the equation:
Ca²⁺(aq) + 2F⁻(aq) → CaF₂(s) ∆H°=-11.5 kJ
When 1 mole of Ca²⁺ and 2 of F⁻ reacts, 11.5kJ are released.
Thus, we need to find moles of reaction to find the heat released and using:
C = SₓmₓΔT
We can find the final temperature as follows:
Moles of reaction:
0.0500L * (0.400mol / L) = 0.0200moles Ca²⁺ = Moles of reaction
Heat produced is:
0.0200 moles * (11.5kJ / mol) = 0.23kJ
Using:
C = SₓmₓΔT
Where C is heat = 230J
S is specific heat = 4.18J/g
m is mass of solution = 100.00g
And ΔT is change in temperature
230J = 4.18J/gₓ100.00gₓΔT
ΔT = 0.55°C
As initial temperature is 23.0°C
Final temperature = 23.0°C + 0.55°C =
23.55°CThe final temperature of the solution is 23.55°C.
We were given the equation
Ca²⁺(aq) + 2F⁻(aq) → CaF₂(s) ∆H°=-11.5 kJ
This means that 1 mole of Ca²⁺ and 2 of F⁻ reacts to form CaF₂ and 1.5kJ is released.
The formula we need to use is C = SₓmₓΔT
where c is heat, s is specific heat, m is number of mole and ΔT is temperature change.
We need to find the moles of reaction first
Moles of reaction = 0.0500L × (0.400mol / L) = 0.0200moles Ca²⁺
Heat produced = 0.0200 moles ×11.5kJ / mol = 0.23kJ
We can then substitute into the formula
C = SₓmₓΔT
C = 230J
S = 4.18J/g
m = 100.00g
ΔT= ?
230J = 4.18J/gₓ100.00gₓΔT
= 0.55°C
Since the initial temperature is 23.0°C
The Final temperature will be 23.0°C + 0.55°C
=23.55°C
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Calculate ΔHrxn for the following reaction:CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g)Use the following reactions and given ΔH′s.C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ
Answer:
ΔH= -390.3kJ
Explanation:
Using Hess's law, we can obtain ΔHrxn from the sum of related reactions.
Using:
(1) C(s) + 2H2(g) → CH4(g) ΔH=−74.6kJ
(2) C(s) + 2Cl2(g) → CCl4(g) ΔH=−95.7kJ
(3) H2(g) + Cl2(g) → 2HCl(g) ΔH=−184.6kJ
(2) - (1):
CH4(g) + C(s) + 2Cl2(g) → CCl4(g) + C(s) + 2H2(g)
CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g)
ΔH= -95.7kJ - (-74.6kJ) = -21.1kJ
This reaction + 2*(3):
2H2(g) + 2Cl2(g) + CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g) +4HCl(g)
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
ΔH= -21.1kJ + 2*-184.6kJ
ΔH= -390.3kJwhat is Acid and any type of acid
Answer:
Acid is the substance which gives H+ ions when dissolved in an aqueous solution and tastes sour.
Types of acid
Strong acidWeak acidAnswer:
An acid is a molecule or ion capable of donating a proton (hydrogen ion H+) or, alternatively, capable of forming a covalent bond with an electron pair.
Explanation:
Hope this helped!
PLEASE HELP!!!!! And thanks in advance
5. Which two body systems work together to bring oxygen into the body's cells
and take carbon dioxide away?
A. Nervous and endocrine
B. Respiratory and digestive
C. Respiratory and circulatory
D. Muscular and skeletal
Answer:
C
Explanation:
the respiratory system and the circulatory system work closely together to deliver oxygen to cells and to get rid of the carbon dioxide the cells produce. The circulatory system picks up oxygen in the lungs and drops it off in the tissues, then performs the reverse service for carbon dioxide.
The two-body systems that work together to bring oxygen to the body's cells and remove carbon dioxide are the RESPIRATORY system and CIRCULATORY system (Option C).
The red blood cells of the circulatory system transport oxygen from the lungs and other nutrients to all the cells of the body, which are required to carry out a process called cellular respiration.
Moreover, carbon dioxide is also transported in the red blood cells to the lungs in the opposite direction.
The alveoli in the lungs of the respiratory system function to absorb oxygen from the air through the process of inhalation and subsequently eliminate carbon dioxide through exhalation.
In conclusion, the two-body systems that work together to bring oxygen to the body's cells and remove carbon dioxide are the RESPIRATORY system and CIRCULATORY system (Option C).
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Why are there multiple ways to represent molecules
Answer:
The different ways to represent compounds are chemical formulas and molecular models. There are so many ways to represent compounds so that a particular formula can be used depending upon how much information is provided and how much is needed to be share.
Explanation:
The representation of molecules depends on what property of the molecule we want to explore.
Representation of moleculesA molecule is composed of atoms of molecules. The representation of molecules depends on what property of the molecule we want to explore.
A molecule can be represented using;
Ball and stick modelSpace filling modelNewman projectionsIn each case, a particlar feature of the molecule is more vividly expressed.
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#SPJ2
BaO2 is a peroxide. Why?
Answer:
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will give branliest
How many grams of liquid water are produced when 60 grams of ice melt? Explain why.
60 Grams are produced due to the fact that it may not produce more due to the certain capacity that varies on the size of the cube.
Why do scientists' study and synthesize new transuranium elements in the laboratory?
Explanation:
Nuclear structure and stability
Although the decay properties of the transuranium elements are important with regard to the potential application of the elements, these elements have been studied largely to develop a fundamental understanding of nuclear reactions and nuclear and atomic structure.
Calculate the mass percent composition of iron for the third one of these iron ores.
Iron is mined from the earth as iron ore. Common ores include Fe2O3 (hematite), Fe3O4 (magnetite), and FeCO3 (siderite).
Answer:
[tex]\% Fe=48.2\%[/tex]
Explanation:
Hello!
In this case, since the percent composition of an element in a compound is given by:
[tex]\% i =\frac{z_i*m_i}{MM}*100\%[/tex]
Whereas i represent the element in the compound for which we want compute the mass percent. As required for siderite, FeCO3 whose molar mass is 115.854 g/mol, and knowing there is one iron atom there with an atomic mass od 55.85 g/mol, the mass percent of iron there is:
[tex]\% Fe=\frac{1*55.85}{115.854}*100\%\\\\\% Fe=48.2\%[/tex]
Best regards!
Bond Energy
Using the table calculate the overall energy change for this reaction.
1. How much energy is needed for bond breaking?
2. How much energy is needed for bond making?
3. What is the overall energy change? (overall energy change = reactants - products)#
4. Can you create an energy level diagram to represent this reaction?
H H
H-CEC-H
- H-C-C-H
11
+
2H-H
HH
Prom the table of the values of bond enthalpy, the values we need are:
Bond
Enthalpy (kJ/mol
H-H
432
Сас
239
CH
413
c-c
347
Which statement describes a major drawback of the Bohr model that caused scientists to replace it?
(A) It worked only for helium and larger atoms.
(B) It did not identify the distance between an electron and the nucleus.
(C) It contradicted the Heisenberg uncertainty principle.
(D) It stated that spectral lines of atoms are similar.
on edgen
Answer:
C.it contradicted the heinsberg uncertainly principle
Answer:
C.it contradicted the heinsberg uncertainly principle
Explanation:
Which of the following elements will lose electrons to form an ion
Answer:
Metals
Explanation:
Metallic elements are renowned for their ability to freely lose electrons to form ions.
This is because metals are electropositive in nature. When a substance is electropositive, it readily wants to lose electrons and form positive ions.
Non-metals prefers to gain electrons and are electronegative.
The magnitude of one Kelvin, one Celsius degree, and one degree on the absolute temperature scale is the same. true or false . please explain it .....
Answer:
false
Explanation:
I don't think centigrade ranges from 0 to 100 and kelvin 237 and 373 absolute -273°c and 0K
Answer:
false............................
1. Is it possible to distinguish DNA and RNA structures by using Bial’s Test? Explain.
2. What are the functions of orcinol and FeCl3 in Bial’s Test.
Answer:
yes and thats all i know
Explanation:
Which order system shows the levels of organization from largest to smallest
organism, organ system cell organ tissue
organism tissue organ system organ cell
organism organ organ system cell tissue
organism organ system organ tissue cell
Answer:
3) organism organ system organ tissue cell
Explanation:
What element produced the unknown emission spectrum?
Answer:
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state.
Which of the following indicates that an endothermic reaction has occurred?
Heat is released
Water is formed
Salt is produced
Temperature decreases
ive seen people say that its A but I don't think so because heat is released when its an exothermic reaction not an endothermic.
will mark brainiest if you get it right
Answer:
Temperature decreases
Explanation:
The correct answer that indicates that an endothermic reaction has occurred would be a reaction in which the temperature decreases.
An endothermic reaction is a reaction in which energy in the form of heat is absorbed from the surrounding. Hence, the final temperature of an endothermic reaction is usually lower than the initial temperature.
Endothermic reactions are the complete opposite of exothermic reactions in which heat is given off in the course of the reactions. Hence, the temperature of the reaction in exothermic reactions increases instead of decreasing.
In summary, a decrease in temperature of a reaction is an indication that heat has been absorbed during the course of the reaction and such a reaction is said to be endothermic.
Answer: Temperature Decreases
Explanation: Endothermic reaction is when heat is released meaning the temperature will decrease.
A student needs to use the metric system while measuring the length of a box. Which units should he use?
AWNSER FAST PLEASEEE
Answer:
Centimeters or milimeters.
Explanation:
The answer depends on the size of the box.
The metric system base unit for length is the meter. Centimeters and milimeters are thus also part of the metric system.
If the box is a "regular-sized" box that we use to put stuff in (books, presents, etc), then centimeters would be the most appropiate.
If we're talking about those tiny boxes that are printed on paper (for example in some notebooks) then milimeters would be the most appropiate.
Answer:
Centimeters
Explanation:
Suppose there is a gaseous mixture of nitrogen and oxygen. If the total pressure of the mixture is 480 mmHg, and the partial pressure of nitrogen is 290 mmHg, calculate the partial pressure of oxygen in the mixture using Dalton's law.
Answer:
Partial pressure of oxygen = 190 mmHg
Explanation:
From the question;
Mixture contains only nitrogen and oxygen
Total pressure of the mixture = 480 mmHg
Partial pressure of nitrogen = 290 mmHg
Dalton's law states that the pressure of a system is as a result of the sum of the partial pressures of the individual components of the mixture. This means that in this mixture;
Pressure of mixture = Partial Pressure of Nitrogen + Partial Pressure of Oxygen
480 = 290 + Partial pressure of oxygen
Partial pressure of oxygen = 480 - 290
Partial pressure of oxygen = 190 mmHg
What would happen if you shone a lazer light into a glass of water?
Answer:
Reflection/change of direction
Explanation:
When the light of the laser hits the glass of water, it reflects and goes another direction. It's basically just a change of direction. The light is mostly in the glass of water and just some reflecting off of it.
How to make the solar oven using the following materials
-pizza box
-aluminium foil
-mirror
-hot glue
-chopstick
Answer:
hot glue
Explanation:
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Add oxidation numbers to the following reaction: 2 H3PO4 (aq) + 2 Cr(s) → 2 CrPO4 (aq) + 3 H2(g). Identify the atom that is oxidized and identify the oxidizing agent.
The atom that is oxidized : Cr
The oxidizing agent : H₃PO₄
Further explanationReaction
2 H₃PO₄ (aq) + 2Cr(s) → 2 CrPO₄ (aq) + 3H₂(g)
Atoms undergoing a reduction reaction (decrease in oxidation number) and an oxidation reaction (increase in oxidation number)
Reduction (+1 to 0)H⁺(in H₃PO₄) =+1
H₂=0
Oxidation (0 to +3)Cr = 0
Cr³⁺(in CrPO₄ )
the oxidizing agent.⇒which undergoes a reduction reaction and oxidizes another compound/element : H₃PO₄
in which beakers are the particles moving the most slowly
A system absorbs 191 kJkJ of heat and the surroundings do 120 kJkJ of work on the system. Part A What is the change in internal energy of the system?
Answer: the change in internal energy of the system is 311 kJ
Explanation:
Given that;
A system absorbs a heat dQ = 191 kJ
And the the surroundings do work on the system dW = 120 kJ
change in internal energy of the system = ?
We take a look at the first law of thermodynamic
Initially the system absorbs energy ( dQ =1 91 kJ) as heat.
Then the surroundings do work (dW = 120kJ) on the system,
Hence the system gains 120 kJ more.
The total energy change is = heat + work
dU = dQ + dW
dU = 191 + 120
dU = 307 kJ
change in internal energy = 311 kJ
Therefore the change in internal energy of the system is 311 kJ
The nucleus of an atom is made up of which of the following combinations of particles?
Answer: Atoms of different elements are found to have different number of protons, neutrons, and electrons. To distinguish one atom from another or to classify the various atoms, a number which indicates the number of protons in the nucleus of a given atom, is assigned to the atoms of each identified element. This number is known as the atomic number of the element. The atomic numbers for some of the elements which are associated with the study of semiconductors are given in the following table.
Explanation:
Element Symbol Atomic Number
Silicon Si 14
Germanium Ge 32
Arsenic As 33
Antimony Sb 51
Indium In 49
Gallium Ga 31
Boron B 5
Answer:
[tex]\boxed {\boxed {\sf Protons \ and \ neutrons}}[/tex]
Explanation:
The atom is made up of two main parts: the nucleus and the electron cloud.
The nucleus is the center and has two subatomic particles: the protons (positive charge) and the neutrons (no/neutral charge). The nucleus as a whole has a positive charge, since the neutrons don't provide a charge.
The electron cloud surrounds the nucleus and houses the negatively charged electrons in a "cloud" of energy levels.
So, the nucleus of the atom is made up of protons and neutrons.
write the formular of the compound formed when element D and oxygen react together
Answer:
D oxide
Explanation:
Hope this helped!
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11
Which statement correctly describes both gases and liquids?"
Answer:
what are the statments?
Explanation: