How many valence electrons are in each atom? a. potassium C. magnesium b. carbon d. oxygen
Help!! < PHYSICAL SCIENCE>
describe how energy changes from a usable form to a less usable form in a buildings heating system
Answer:
The warm exhaust from the natural gas heater
is the result of taking usable energy (in the
natural gas), using some of it, then releasing
the less usable form (exhaust). or you can write -> Electricity is a usable form of energy, but heat is not. Heat is simply dissipated to the surroundings as a result of temperature gradient. Thus, energy is transformed from usable to non-usable form.
Define pollination, fertilization and photosynthesis process
Use the Word Correctly in a Sentence
Ion
0.53g of acetanilide was subjected to kjeldahl determination and the ammonia produced was collected in 50cm3 of 0.50M of h2so4.on dilution 250cm3, the acid was titrated against 25cm3 portion of 0.05M sodium carbonate solution. 13.60 of acid was required for each titration. What is percentage of nitrogen in acetanilide
Answer:
10.57% of N in acetanilide
Explanation:
All nitrogen in the sample is converted in NH₃ in the Kjeldahl determination. The NH₃ reacts with H₂SO₄ as follows:
2NH₃ + H₂SO₄ → 2NH₄⁺ + SO₄²⁻
The acid in excess in titrated with Na₂CO₃ as follows:
Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂
To solve this question we must find the moles of sodium carbonate = Moles of H₂SO₄ in excess. The added moles - Moles in excess = Moles of sulfuric acid that reacts:
Moles Na₂CO₃ anf Moles H₂SO₄ in excess:
0.025L * (0.05mol / L) = 1.25x10⁻³ moles Na₂CO₃ / 0.01360L =
0.09191M * 0.250L = 0.0230 moles H₂SO₄ in excess.
Moles H₂SO₄ added:
0.050L * (0.50mol / L) = 0.0250 moles H₂SO₄ added
Moles that react:
0.0250 moles - 0.0230 moles = 0.0020 moles H₂SO₄
Moles of NH₃ = Moles N:
0.0020 moles H₂SO₄ * (2mol NH₃ / 1mol H₂SO₄) = 0.0040 moles NH₃ = Moles N
mass N and mass percent:
0.0040 moles N * (14g / mol) = 0.056gN / 0.53g * 100 =
10.57% of N in acetanilideWhich answer choice describes all nonmetals? A. All of the elements of Period 2 in green boxes B. Hydrogen and all of the other elements in orange boxes C. All of the elements of Group 18 in orange boxes D. Hydrogen and all of the elements in blue boxes
How many grams of Fe2O3 are needed to produce 51.9 g of CaO?
Answer:
98.8g (3 s.f.)
Explanation:
Use the mole = mass/mr equation to find the moles of CaO, then use the molar ratio to find the moles of Fe2O3, which is the same as CaO, (assuming the ratio is 1:1, as you haven't stated it clearly in the question). Then use the equation and input to find Mass, which is 98.8g to 3 s.f.
Please help me figure this question out I’ll mark you brainiest. The balanced equation would be 2Na + 2Cl = 2NaCl. Hope that helps ya solve it.
Answer:
I think c.............
Which term refers to an electrochemical cell that uses a spontaneous redox reaction to produce an electric current?
electrolyte
voltaic cell
electrolytic cell
cathode
all about Henry Mosléy?
Answer:
Henry Moseley was an English physicist whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number.
Complete and balance the equation. Show your work on paper and submit a screenshot to
Canvas.
N_20_5
A. Not possible
B. 2, 2,5
C. 2,5,2
D. 2,2,4
Answer:
A
Explanation:
because need more number to complete the balance equation
Perform the following operation
and express the answer in
scientific notation.
3.60x10-12 + 3.60x10-11
Answer:
3.60X10^-12 is equal to 0.360X10^-11 (move decimal one place left)
Now you can add 3.60X10^-11 and 0.360X10^-11:
3.60X10^-11 + 0.360X10^-11 = 3.96X10^-11
You're really just adding 3.60 to 0.36 since the "X10^-11" is the same for both.
C4H10+ 02 → CO2 +H2O
balance the equation
Answer:
C4H10 + 502 -> CO2 + 5H20
......
.......
6.
Ammonia (NH3) acts as a weak base in aqueous solution. What is the acid that reacts with this base
when ammonia is dissolved in water?
(A) NHA
(B) H2O
(C) Oxygen, which is always dissolved in water
(D) None of the above, there are no acids in pure water
Answer:
90% of people marry there 7th grade love. since u have read this, u will be told good news tonight. if u don't pass this on eight comments your worst week starts now this isn't fake. apparently if u copy and paste this on ten comments in the next ten minutes you will have the best day of your life tomorrow. you will either get kissed or asked out in the next 53 minutes someone will say i love you.!Explanation:
Ammonia acts as a weak base in aqueous solution. Water is the acid that reacts with this base when ammonia is dissolved in water.
What is a base?According to the Arrhenius concept, base is defined as a substance which yields hydroxyl ions on dissociation.These ions react with the hydrogen ions of acids to produce salt in an acid-base reaction.
Bases have a pH higher than seven as they yield hydroxyl ions on dissociation.They are soapy in touch and have a bitter taste.According to the Lowry-Bronsted concept, base is defined as a substance which accepts protons .Base react violently with acids to produce salts .Aqueous solutions of bases can be used to conduct electricity .They can also be used as indicators in acid-base titrations.
They are used in the manufacture of soaps,paper, bleaching powder.Calcium hydroxide ,a base is used to clean sulfur dioxide gas while magnesium hydroxide can be used as an antacid to cure acidity.
Learn more about base,here:
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If the solubility of sugar is 204/100 mL, how much water will be required to saturate a solution that contains 1608g of sugar?
Which statement describes the solar feature shooting off into space labeled C?
An envelope of plasma surrounding the sun
A stream of glowing gas that shoots out from the sun in an arch
A brief eruption of intense high-energy radiation from the sun's surface
A dark spot appearing from time to time on the sun's surface
Answer:
The correct answer is - An envelope of plasma surrounding the sun.
Explanation:
In the provided diagram the C labeled part of the sun is an envelope of plasma surrounding the sun which is called Solar Corona which makes the outermost layer of the atmosphere of the sun. Solar Corona is hotter in comparison to the surface of the sun itself.
Solar Corona is made up of the fourth state of matter known as plasma that has its magnetic field that determined its structural characteristics. Thus, the correct answer is an envelope of plasma surrounding the sun.
Answer:
person above is correct
Explanation:
I took the quiz and got it right.
Chem. Assignment
I need help...with answers 1-6 thanks
Answer:
1. an educated guess
2. data
3. what changes in experiment
4. what stays the same in both groups
5. the group where nothing changes, normal
6. group with independent variable, what's being tested
20 points!! Please help ASAP!
Determine the molarity (M) of a solution that is made by dissolving 0.35 moles NaCl in water in order
to make 500 mL of solution. *For Molarity problems, convert mL to L
Answer:
78 ml
Explanation:
1)Why do clouds usually form high in the air instead of near Earth's surface?
a) High in the atmosphere is less dense
b) High in the atmosphere contains less oxygen
c) High in the atmosphere is usually cooler
d) High in the atmosphere has less air pressure
5) Which element has the lowest first ionization energy?*
Li
K
Na
Answer:
K
Explanation:
Ionisation energy is the energy required for electron loss and the higher the occupied energy levels=higher atomic radius=the lower the ionisation energy thus k=2.8.8.1
Na=2.8.1
Li=2.1
Question 1
Calculate the pressure in a 12 Liter tank containing 2.52 moles of argon gas at 5°C?
a 8.2 atm
b 2.4 atm
с 0.3 atm
d 5 atm
PLEASE HELP
Answer:
D
Explanation:
Name
12. A chemist places a piece of solid magnesium in an aqueous solution of copper (II)
sulfate and notices a reaction. Pieces of solid copper dropped out of the solution as a
precipitate and magnesium sulfate was formed.
a) Give a balanced formula equation (with state symbols) for this reaction (3 marks)
Answer:
Explanation: Mg(s) + CuSO4 (aq) -> Cu(s) + MgSO4 (aq)
Substances that absorb energy in the form of heat are
A) Exothermic
B) Endothermic
C) Isothermic
Answer:
Substances that absorb energy in the form of heat are
b)endothermic.
hope it helps :)
1. When _____
are added or removed from an atom, _____
is formed
Answer:
1.) protons or electrons 2.) ion
Explanation:
Calcium carbonate decomposes into
calcium oxide and carbon dioxide.
The mass of calcium carbonate that
decomposes is 57 g. At the end of
the experiment, the mass of the
products were only 45 g. What can
we conclude from this information?
Answer:
The mass of carbon dioxide formed is 12g.
Which of the following reactions had the greatest percent yield?
a.Theoretical yield 52.3 g; actual yield 50.7g
b.Theoretical yield 17.1 g; actual yield 15.7g
c.Theoretical yield 38.8 g; actual yield 36.2 g
d.Theoretical yield 24.6 g; actual yield 22.5 g
Answer:
Option A
Explanation:
As we know
Percent yield is the ratio of actual yield/theoretical yield
a) Percent yield - Theoretical yield 52.3 g; actual yield 50.7g = 0.97 = 97%
b) Percent Yield - Theoretical yield 17.1 g; actual yield 15.7g = 92%
c) Percent Yield - Theoretical yield 38.8 g; actual yield 36.2 g = 93%
d) Percent Yield - Theoretical yield 24.6 g; actual yield 22.5 g = 91%
Hence option A is correct
what is the mass number for an atom that has 36 protons 36 electrons and 40 neutrons
Answer:
76
Explanation:
Mass number = number of protons plus the number of neutrons
So, 36 + 40 = 76
Explain how to count the number of elements in a compound.
Answer:
Simply identify what elements are in a compound
Explanation:
For example in NaCl we have sodium (Na) and Chlorine (Cl)
In order to do this you would need to recognise the symbols for a certain element: O for oxygen; N for nitrogen; H for hydrogen etc.
1.The water molecule is-
A. Slightly negative near the hydrogen atoms and slightly positive near the oxygen atom
B. Slightly positive in all areas of the molecule
C. Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms
D. The same charge in all areas of the molecule
Answer:
C.
Explanation:
Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms