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Related Questions
calculate the oxidation numbers of the elements in this equation
2 Al2O3 → 4 Al + 3 O2
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Explanation:
Answer
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The rule used here is that the algebraic sum of the oxidation numbers of all the atoms a molecule is zero.
Al2O32× ( oxidation number of Al)+3× ( Oxidation number of O ) = 0
2× ( Oxidation number of Al) +3(−2)=0
2× ( oxidation number of Al) +6
∴ Oxidation number of Al =+3
The half-life of strontium-90 is about 29 years. How many half-lives have elapsed when 6.25% of
O 1
02
3
оо
Answers
The question is incomplete, the complete question is;
The half-life of strontium-90 is about 29 years. How many half-lives have elapsed when 6.25% of a strontium- 90 sample remains in the container?
Answer:
4 half lives
Explanation:
From;
N/No = (1/2)^t/t1/2
N= amount of strontium-90 present at time t
No= amount of strontium-90 originally present
t= time taken
t1/2 = half life of strontium-90
But N= 0.0625No
Hence;
0.0625No/No = (1/2)^t/29
0.0625 = (1/2)^t/29
(1/2)^4 = (1/2)^t/29
4 = t/29
t = 4 × 29
t= 116 years
Hence four half lives have elapsed
The radius of the large cylinder of a hydrolic press
20cm and that of the small cylinderis 5 cm. If a force of 100N is applied on the small piston Calculate the force on the large piston. if the piston of the small cylinder move through a distance of 0.4m through what distance can the large piston be raised
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Answer: 1) 400N
2)1.6
Explanation:
1) 5cm = 100N of force
so
20cm=400n
2) 0.4 X 4 = 1.6
PLEASE HELP!!
What is the reduction half-reaction for 2Mg + O2 —> 2MgO?
A) Mg -> Mg2+ + 2e-
B) O2 + 4e- -> 2O2-
C) Mg2+ + 2e- -> Mg
D) 2O2- -> O2 + 4e-
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Answer:
O2 + 4e- -> 2O2-
Explanation:
You have to start by assigning the oxidation numbers, which eventually will lead to every atom of oxygen taking 2 electrons and every molecule of oxygen will take 4 electrons.
(you can ignore this explanation, my answer wasn't long enough).
are there other universes ??
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Answer:
Some theories say that there is only one universe and that everything is inside the universe and there is nothing outside the universe but some other theories say that there are more Universes which has the opposite copy of all the planets in our universe.
Which property can be attributed to an ideal gas?
A The particles occupy a significant volume.
B The collisions of the particles are elastic.
C The particles move at different velocities.
D The particles move in definite patterns.
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What happens to the intensity of light emitted from stars the further away the star is from us?
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Answer: stars vary in their effective temperature and colour. A hot star radiates more energy per second per metre surface area than a cooler star. Does this then mean that a hot star is going to appear brighter to us than a cooler one? The answer to this actually depends on a few factors
Explanation: pa brainiest po
Form similar pairs of words.
Boron : B :: Beryllium :
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Answer:
Boron : B :: Beryllium :Be
Explanation:
Boron is an element found in group 13 of the periodic table. It has three electrons in its outermost shell hence a valency of 3.
Beryllium is an element in group two of the periodic table. It has a valency of two hence there are two electrons in its outermost shell.
Boron and beryllium are similar words. The symbol of boron is B while the symbol of beryllium is Be.
A circuit is set up with two parallel resistors, each of a resistance of 250Ω.
b. If another resistor of resistance 300Ω is added in series with these two parallel resistors, what is the total
resistance?
c. If a voltage of 120V is put across the circuit in b, what will the current be in the circuit?
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Answer:
425 and 0.28A
Explanation:
Resistance for resistors in parallel
1/ R = 1/250 +1/250
=0.008
R = 1/ 0.008 = 125
Total resistance
R= 125+ 300
=425
...
V= IR
I= V/R
I = 120/425
= 0.28 A
Which of the following demonstrates how chemicals can help the environment?
A. Herbicides can get rid of unwanted weeds.
B. Pollutants can be prevented from entering the environment.
C. Pesticides can kill insects that eat garden plants.
D. Lime can be used to adjust the pH in lakes that are too acidic.
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To solve this we must be knowing each and every concept related to environment. Therefore, the correct option is option D among all the given options.
What is environment?A basic definition of such an environment is a system that includes all abiotic and biotic components that impact human existence. All flora and animals are biotic components, whereas abiotic components comprise water, sunshine, air, temperature, and so on.
An environment's resources might be any issue, service, or specifics that are beneficial to society and humans. They might be anything that meets the demands of daily living. Lime can be used to adjust the pH in lakes that are too acidic demonstrates how chemicals can help the environment.
Therefore, the correct option is option D.
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_ As + _ NaOH → _Na3ASO3 + __ H2
Answers
Answer:
2As + 6NaOH =2Na3AsO3 +3H2
Explanation:
2As + 6e- = 2As³ ,this is an oxidation reaction
6H¹ +6e- =6H⁰ ,this is reduction process
the above reaction exhibit a redox redox reaction As acts as a reducing agent while NaOH acts as an oxidizing agent.
A scientist formulates the following hypothesis: If plants of the same species
are grown under the same conditions, the amount of fertilizer the plants
receive will affect their growth rate. Which variable will be a responding
variable in the experiment designed to test this hypothesis?
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Answer:
Growth rate
Explanation:
The responding variable, also known as the DEPENDENT VARIABLE, is the variable that responds to changes or manipulations made to another variable (independent or manipulable variable) in the experiment. It is the measured variable of an experiment.
According to the hypothesis provided for this investigation, the scientist wants to determine if the amount of fertilizer plants of the same species receive will affect their growth rate when planted in the same condition. This shows that the independent variable is the amount of fertilizer to be used while the RESPONDING VARIABLE OR DEPENDENT VARIABLE is the GROWTH RATE OF THE PLANTS because it responds to the amount of fertilizer.
Chloe’s teacher gives her and her lab partner soil samples from different parts of the city: the park, the area next to a pond, the school, and a neighborhood. Chloe’s teacher also gives her a soil tester kit, which determines the pH of the soil. Chloe and her lab partner need to determine the pH of each soil sample and then compare them.
Fill in the blank with the word that best completes the statement.
This investigation is a(an)______investigation.
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Answer:
an
Explanation:
It is AN because investigation starts with I ( i is a vowel). When there are vowels we use An.
Pls mark me brainliest!
calculate the mass m of 6.50 moles n of kbr m
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Answer:
773.51495 grams
Explanation:
1 moles KBr to grams = 119.0023 grams
6.5*119.0023 = 773.51495 grams
will give u brainliest plzz help
Answers
Answer:
4.76 mol / L
Explanation:
The process that takes place is:
Sc₂(C₂O₄)₃ → 2Sc⁺³ + 3C₂O₄⁻²Assuming we have 1 L of the solution, we would have 2.38 moles of Sc₂(C₂O₄)₃.
We then convert 2.38 moles of Sc₂(C₂O₄)₃ into moles of Sc⁺³, using the stoichiometric coefficients:
2.38 mol Sc₂(C₂O₄)₃ * [tex]\frac{2molSc^{+3}}{1molSc_2(C_2O_4)_3}[/tex] = 4.76 mol Sc⁺³Finally we calculate the concentration of scandium ion (Sc⁺³) in mol/L:
4.76 mol Sc⁺³ / 1 L = 4.76 mol/LGeometric isomers have profound effects on the physical properties of compounds. Naturally occurring fatty acids generally adopt a cis geometry. What's one physical property affected by this geometry? (HELP ASAAAP!)
A)
Color
B)
Taste
C)
Smell
D)
Melting point
Answers
Taste yayququwiiqqiiqiqiwiw
Answer:
melting point
Explanation:
the six gas laws ASAP PLS
Answers
A 12 inch object is placed 30 inches in front of a plane mirror
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Answer:
12 inches
Explanation:
i got it right in the Same question
[tex]what \: is \: acid \: \: \: {?} [/tex]
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meaning:An acid is a chemical substance, usually a liquid, which contains hydrogen and can react with other substances to form salts. Some acids burn or dissolve other substances that they come into contact with.
Answer:
Hope it help you#CarryOnLearningDescribe two situations in which you observed or performed an energy transformation. For each situation, name the starting form of energy and an ending form of energy.
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Answer:
The Sun transforms nuclear energy into heat and light energy.
Our bodies converting chemical energy in our food into mechanical energy for us to be able to move.
An electric fan transforming electrical energy into kinetic energy.
Which of the following represents an element ? H2O H2 NaCl CaCO3
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Answer:
H₂
Explanation:
H₂ is hydrogen in its elemental form.
H₂O, NaCl, and CaCO₃ are all examples of elements added together to create compounds.
Write the complete and net ionic equations for the following reactions. If only the reactants are given, predict the products and balance the equation first.
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Explanation:
u can put them in order crossed are spectator ions. hope this helps:)
Vhon Anadome
Atomic nucleus questions
Which of the following decay processes results in the largest change in mass of a nucleus?
Choose 1 answer:
А
Beta decay
Gamma decay
Neutron emission
D
Alpha decay
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Answer:
d
Explanation:
what are microorganisms
Please i really wanna know
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Answer:
Are the organism we cant see with our bare eyes. We only see them with the help of a microscope
Explanation:
A wheelbarrow can be used to help lift a load, such as a pile of dirt, and then push the load across a distance.
A man pushes a wheelbarrow.
Which simple machines make up a wheelbarrow?
a pulley and an inclined plane
a wheel and axle and a lever
a pulley and a wheel and axle
a lever and a wedge
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Answer: it consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow.
Explanation:
Answer:
B
Explanation:
B)
examples of metal non-metal and semi metal
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Answer:
Semi : Boron [B] Non-Metal : Carbon [C] Metal : Manganese [Mn]
Explanation:
Periodic table I'm guessing!
PLEASE HELPP!!
What is the empirical formula of the compound is C22H44O22
A. CH2O
B. C3H6O3
C. C2H4O2
D. CHO
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Answer:
The answer is C
Which prefix indicates a molecule with 2 carbon atoms?
O A. Eth-
O B. Oct-
O c. Hex-
O D. Meth-
The answer is A.Eth-
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The prefix indicates a molecule with 2 carbon atoms is eth- and the correct option is option A.
What is IUPAC Nomenclature?
The IUPAC system of nomenclature is a set of logical rules framed which are mainly aimed at giving an unambiguous name to an organic compound.
IUPAC stands for International Union of Pure and Applied Chemistry
A prefix to the name comes before the molecule. The prefix of the molecule's name is based on the number of carbon atoms.
For example, a chain of six carbon atoms would be named using the prefix hex-.
The suffix to the name is an ending that is applied that describes the types of chemical bonds in the molecule.
Therefore, The prefix indicates a molecule with 2 carbon atoms is eth- and the correct option is option A.
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At the midpoint of a titration curve ________. At the midpoint of a titration curve ________. The concentration of a conjugate base is twice that of the concentration of a conjugate acid The pH equals the pKa The ability of the solution to buffer is at its least effective The concentration of a conjugate base is 1/2 that of the concentration of a conjugate acid
Answers
Answer:
The concentration of a conjugate base is twice that of the concentration of a conjugate acid
Explanation:
This is because at the midpoint, the number of moles of acid equals half the number of moles of base at the midpoint. This means that at the midpoint, half the analyte has been titrated.
Since the concentration of the conjugate acid is half that of the conjugate base at the midpoint, this implies that the concentration of the conjugate base is twice that of the conjugate acid.
Thus, at the midpoint of a titration curve the concentration of a conjugate base is twice that of the concentration of a conjugate acid
list 8 functions of petroleum
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Petroleum products include fuel oils for heating and electricity generation.
It is a feedstocks for making the chemicals and plastics.
We use petroleum to produce electricity.