Answer:
The oxidation state of N in the KNO3 is +5
Explanation:
Oxidation rules:
1. Oxygen is -2, unless in peroxides.
2. Group 1 metals = +1
3. Group 2 metals = +2
4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.
5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.
So, the given formula represents the salt compound formula unit of potassium nitrate: KNO3
The formula unit is uncharged.
From our rules, we know that,
O = -2
And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.
K = +1
N = x
O = -2
Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.
+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)
x - 5 = 0
x = 5
Therefore, the oxidation number of N in KNO3 is +5.
What is the change in enthalpy of the first reaction below, given the enthalpies of the other two reactions?
Here's the reactions:
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
2C(s) + O2(g) → 2CO(g)
C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
Answer:
∆H0 = -222kJ/mol
Explanation:
Using Hess's law, we can find the ΔH of a reaction from the sum of another related reactions as follows:
Using the reactions:
(1) C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
(2) CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
Twice (1):
2C(s) + 2O2(g) → 2CO2(g) ∆H0= 2*-394 KJ/mol = -788kJ/mol
The inverse reaction of (2):
-(2) CO2(g) → CO(g) + 1/2 O2(g) ∆H0= 283 KJ/mol
Twice this reaction:
2*-(2) 2CO2(g) → 2CO(s) + O2(g) ∆H0= 2*283 KJ/mol= 566kJ/mol
Now, the sum of 2*(1) - 2*(2) produce:
2C(s) + 2O2(g) + 2CO2(g)→ 2CO2(g) + 2CO(g) + O2(g) ∆H0= -788kJ/mol + 566kJ/mol
Subtracting the molecules that ar in both sides of the reaction:
2C(s) + O2(g) → 2CO(g) ∆H0 = -222kJ/mol
why is it important of having regular supervision of the market?
how do i calculate the concentration of a certain solution
Answer:
Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.
Plz Help I have One more time To retake and I can't fail it..
[tex]option(a)[/tex]
Explanation:
You answer is correct as you move from left to right across a period. But, the question is asked regarding to the right to left across a period. So, as you move from right to left across a period, you can find firstly Non-metals, secondly Metalloids, and lastly Metals.
molecular formula of ammonium nitrite using cris method
Answer:
By using the criss cross method,the -1 charge of nitrate ion is shifted to ammonium ion and +1 charge of ammonium ion is shifted to nitrate ion. In this way, the final formula NH4NO3 is formed for the ammonium nitrate.
Mole concept
Calculate the number of iodine atoms in 4.50g of iodine gas
Answer:
0.017g/mol
Explanation:
according to the mole concept to calculate the number of moles of a substance you use the formula
number of moles= mass/molecular mass
=4.5g/254g/mole
=0.017moles
I hope this helps and sorry if it's wrong
The graph shows the change in concentration of one of the species in the reaction
A + B + C→D.
If the graph indicates the reaction rate, then the concentration of which species is plotted?
A
B
C
D
Answer:
its D
Explanation:
Took the test
The specie whose concentration is plotted is D. The rate of reaction is how quickly or slowly hat a reaction proceeds.
Rate of reactionThe term rate of reaction refers to how quickly or slowly hat a reaction proceeds. A reaction rate plot involves the concentration of the species plotted against time.
Now we can see from the plot that concentration is increasing with time. Since the concentration of products increases with time, then the specie whose concentration is plotted is D.
Learn more about rate of reaction: https://brainly.com/question/11256472
What effect does the electrostatic force have?
- Particles without charge repel each other.
- Particles of different masses repel each other.
- Particles of opposite charge repel each other.
- Particles of the same charge repel each other. (ANSWER)
D
Explanation:
Particles of the same charge repel each other
why water molecules remain associated in liquid water
Answer:
Answer: They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.
Answer:
They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.
Explanation:
in which instrument of the following the washer works works as a valve? a)syringe b)hydraulic garage lift c)air pump d)watre pump
Answer:
A
Explanation:
The instrument in which the washer works as a valve is A ; syringe
Each instrument listed have a washer and a valve, but of all the instruments listed above the instrument that its washer works also as a valve is the syringe.
A syringe is composed of a thin tube and a thinner hollow needle attached to the end of the thin tube. the needle is used and take in liquids and also expel liquids from the syringe ( i.e. washer and valve )
hence the instrument that its washer also functions as a valve is the syringe.
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can u plz solve it n send the answer
1. Cl2 + H2O → HOCl + HCl
2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.
3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.
4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.
5. Tincture of iodine is clear and reddish brown liquid.
A galaxy that has an undefined shape is best classified as a(n)
galaxy.
Answer:
irregular galaxy
pls give brainliest :)
Answer:
irregular galaxy
it is undefined shape
how to prepare hydrogen gas
Seeds are organs within the reproductive system of plants. How is the spreading of seeds important to the survival of an organism?
A. An organism must reproduce in order to find a suitable place to live.
B. Although a single organism can survive without reproducing, organisms must reproduce in order to ensure the survival of the species.
C. Although a single organism can survive without reproducing, the organism must spread its seeds in order to protect itself from disease.
D. An organism must reproduce in order to absorb nutrients from the environment. SUBMIT
Answer:
Although a single organism can survive without reproducing, organisms must reproduce in order to ensure the survival of the species.
Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu
Answer:
132.17amu
Explanation:
(14.01+1.01 multiplied by 4)=18.05×2=36.1
36.1+32.07= 68.17
16.00×4=64
68.17+64=132.17
Answer:
132.17 amu
Explanation:
just took the test. got 100
Which of the following statements about periodic trends is true?
O both electronegativity and atomic radius decrease from bottom to top and from left to right on
the periodic table.
O both electronegativity and ionization energy increase from bottom to top and from left to right
on the periodic table.
O both atomic radius and ionization energy increase from bottom to top and from right to left on
the periodic table.
O electronegativity, ionization energy and atomic radius all decrease from bottom to top and from
left to right on the periodic table.
both electronegativity and ionization energy increase from bottom to top and from left to right
on the periodic table.
(07.01 MC)
A potential energy diagram is shown.
70
60
Products
50
40
Potential Energy (kJ)
30
Reactants
20
10
0
Reaction Pathway
What is the activation energy of this reaction? (5 points)
Answer:
the activation energy is 65-30
35
The activation energy of this reaction is 35 kJ.
What is activation energy?Activation energy, in chemistry, the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation or physical transport.
The activation energy is equal to the difference between the threshold energy needed for the reaction and the average kinetic energy of all the reacting molecules.
The activation energy of a reaction is the difference in energy between the threshold energy and energy of the reactants.
Given,
The highest energy for a reaction to happen = Threshold energy = 65 kJ
Energy of the reactants = 30 kJ
Therefore, The activation energy of this reaction is 35 kJ.
Learn more about activation energy here:
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What was the main aim of Cavendish’s work?
Answer:
The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant
Explanation:
I think that's correct
calculate the mass of magnesium needed to make 25g of magnesium oxide
mark brainliest of correct xx
Answer:
15g
Explanation:
First, you need to correct the answer to the previous question. The percentage by mass of Mg in MgO =
Mg = 24.3 amu
O = 16.0 amu
The total mass of MgO = 40.3 amu
To calculate the percent composition of Mg:
% = 24.3/40.3 x 100
% = 60
To calculate the mass of Mg needed to make 25g of MgO:
x/25g = 60%/100%
100x = (25)(60)
100x = 1500
x = 15g
Question:
Nearly the entire world uses the metric system for their measurements. The US is one in of three countries that does not use metric. Would you support changing school curriculum to teach the metric system as the primary measurement system in the US? Why or why not.
(It must be 3-5 sentences long please)
Answer:
I would
Explanation:
I would support the change to the metric system only because it allows children to understand smaller forms of units and measurements. Also, it will allow people in the math and science fields to broaden their knowledge of equations and formulas. Meaning that the scientist and mathematicians will be able to solve more problems in the world right now. Overall, the education system for the children of the United States would benefit from the change in the measurement system.
Some one please Help and Thank you
Answer:
C is the correct answer
Explanation:
most probably
When a vacancy exists in an inner electron shell of an atom (as a result of photoelectric effect, Compton scattering, or bombardment by other electrons), the energy liberated when this vacancy is filled, instead of emerging from the atom as fluorescent radiation, can be transferred to another electron of the atom, thereby ejecting the electron. Such an emitted electron is called a(n) _____ electron
Answer:
The answer is "Auger".
Explanation:
The Auger effect is an effect size when the vacancy of even an atom throughout the inner shell was complemented by the release of even an electron from the same atom. Whenever a central electron is lost, a higher energy level electron can drop into the void and release energy, which can be the result.
HELP ME ASAPPPP PLZZZZZ!!!!!
For the reaction C + 2H2 → CH4, how many grams of hydrogen are required to produce 16.8 moles of methane, CH4 ?
Name the following bases.
Fe(OH)3
- iron(III) hydroxide
- iron(II) hydroxide
- iron hydroxide
Answer:
1
Explanation:
Ferric Hydroxide
3. 1
Fe. (OH)
Fe(OH)3
Answer:
iron(III) hydroxide
Explanation:
I just took the quiz!
Ethylene glycol (antifreeze) has a density of 1.11 g/cm^3. What is the volume (in m^3) of 9.7 tons?(1 ton = 2.000*10^3lb; 1 kg= 2.2046 lb
Answer: The volume of 9.7 tons of given ethylene glycol is 0.0079 [tex]m^{3}[/tex].
Explanation:
Given: Density = 1.11 [tex]g/cm^{3}[/tex]
Mass = 9.7 tons
Convert tons into lb as follows.
[tex]1 ton = 2 \times 10^{3} lb\\9.7 ton = 9.7 ton \times 2 \times 10^{3} \frac{lb}{1 ton}\\= 19.4 \times 10^{3} lb[/tex]
Now, lb is converted into kg as follows.
[tex]1 kg = 2.2046 lb\\1 lb = 0.453592 kg\\19.4 \times 10^{3} lb = 19.4 \times 10^{3} lb \times 0.453592 \frac{kg}{1 lb}\\= 8.79 kg[/tex]
1 kg = 1000 g
So, 8.79 kg = 8790 g
Density is the mass of a substance divided by its volume. Hence, volume of ethylene glycol is calculated as follows.
[tex]Density = \frac{mass}{volume}\\1.11 g/cm^{3} = \frac{8790 g}{volume}\\volume = 7918.92 cm^{3} (1 cm^{3} = 10^{-6} m^{3})\\= 0.0079 m^{3}[/tex]
Thus, we can conclude that the volume of 9.7 tons of given ethylene glycol is 0.0079 [tex]m^{3}[/tex].
How do the substances compare?
hii pls help me to balance chemical equations
ammonia + oxygen ------> nitrogen + water
Answer:
Explanation:
Ammonia = NH3
Oxygen = O2
When these two (2) chemical elements react together, they form two chemical compound which are nitrogen oxide and water.
NH3 + O2 -----> NO + H2O
We would balance the chemical equation like this;
NH3 + 3O2 -----> 4NO + 2H2O
Please hurry this is due tomorrow morning
A student is studying the ways different elements are similar to one another. Diagrams of
atoms from four different elements are shown below.
Which two atoms are of elements in the same group in the periodic table?
F Atom 1 and Atom 2
G Atom 1 and Atom 4
H Atom 2 and Atom 3
J Atom 3 and Atom 4
Answer in detail?? What precautions would you take to protect yourself from an earthquake, when you are at home and when you are outdoors?
Answer:
If you're indoors, stay inside. If you're outside, stay outside. If you're indoors, stand against a wall near the center of the building, stand in a doorway, or crawl under heavy furniture (a desk or table). Stay away from windows and outside doors.
Answer
Protect your head and neck with a large book, a pillow, or your arms. The goal is to prevent injuries from falling down or from objects that might fall or be thrown at you.If you are able, seek shelter under a sturdy table or desk. Stay away from outer walls, windows, fireplaces, and hanging objects.If you are unable to move from a bed or chair, protect yourself from falling objects by covering up with blankets and pillows.If you are outside, go to an open area away from trees, telephone poles, and buildings, and stay there.Plz Help I have One more time To retake and I can't fail it..
Answer:
A
Explanation:
Hydrogen bonds are intermolecular forces of interaction that exist between molecules of a substance in which hydrogen is bonded to a highly electronegative atom. Hydrogen bonds are strong intermolecular forces and account for high melting and boiling points of small molecules such as water. They stem from dipole-dipole interaction between molecules of a substance.
Metallic bonds are bond forces which exist in a metal. Metal cations are held together by a sea of electrons via electrostatic interaction.
The ionic bond is formed by transfer of electrons from one atom to another leading to the formation of an ion pair held together by electrostatic attraction.
Metallic bonds and hydrogen bonds are much weaker than ionic bonds. Ionic compounds are known to have high melting and boiling points.
