Answer:
For your first question, Curium does not occur naturally on Earth, meaning that it is not produced naturally on Earth. However, it can be formed in nuclear reactors.
For your second question, Curium has been used to provide power to electrical equipment used on space missions, but doesn't seem to be that important overall.
Explanation:
Hope this helped!
If a radioactive substance has a half-life of 9 days what fraction of its original mass would remain after 27 days? *
Answer:
1/8
Explanation:
If the substance has a half-life of 9 days, that means that after 9 days, half of it will be left. So, after 18 days, one-fourth will be left. And after 27 days, 1/8 would be left. It's kind of like an exponential function, if that helps.
If a radioactive substance has a half-life of 9 days, the fraction of its original mass that would remain after 27 years will be 1/8.
What is half-life?Half-life is the time when a radioactive substance is decayed half.
If the radioactive substance has a half-life of 9 day. It means it will be decayed half after 9 days. The radioactive substance will be 1/4 decayed in 18 days. The substance will be 1/8 decayed in 27 days.
Thus, the correct option is 1/8 days.
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write down any four uses of solution
.I will mark him\her as brilliant
Answer:
because it will help u
because it will make u to understand the question very well
2.
Corona virus has a spherical shape. Its diameter is approximately 120 nm. How
many of them can sit side by side to form a circle around a piece of human hair.
Take the diameter of a hair as 50 um. (Select the nearest value to your calculation
result)
a) 1.23x10 12
b) 4.45 x106
C) 1312
d) 417
Answer:
417
Explanation:
50um is
50000nm
50000:120=417
compound
element + element
1:Synthesis
2:Decomposition
3:Single Replacement
4:Double Replacement
5:Combustion
Answer:
4
Explanation:
Because of single replacement the ideal shape comes in form
I need help and fast plzzzzzzzzz
Answer:
A is condensation
B is Conduction
C is erosion
D is radiation
E is deposition
Explanation:
Which of the following equations demonstrates an actual chemical reaction that forms a new substance?
A1: ZN + 2HCl → 2NCl2 + H2
A2: H2O + NaCl → H2O
A3: Zn + Al + Cu → Zn + Cu + Al
A4: C12H22O11 + H2O → H2O + C12H22O11
Answer: [tex]Zn+2HCl\rightarrow ZnCl_2+H_2[/tex]
Explanation:
A chemical reaction is said to have occured when reactants react to form new products where the atoms undergo a change in bonding.
From the given reactions:
1. [tex]Zn+2HCl\rightarrow ZnCl_2+H_2[/tex]
Here Zn combines with hydrochloric acid to form zinc chloride and hydrogen.
2. [tex]H_2O+NaCl\rightarrow H_2O[/tex]
Here water remains as such as no new substance is formed.
3. [tex]Zn+Al+Cu\rightarrow Zn+Cu+Al[/tex]
Here no new substance is formed.
4. [tex]C_{12}H_{22}O_{11}+H_2O\rightarrow H_2O+C_{12}H_{22}O_{11}[/tex]
Here no new substance is formed.
Thus [tex]Zn+2HCl\rightarrow ZnCl_2+H_2[/tex] demonstrates an actual chemical reaction that forms a new substance
Answer:
hope this helps you!
Explanation:
3
Solve and derive the unit for Power
Answer:
Unit of power is watt
Explanation:
Power = rate of doing work
or
Power, P = W/t
Where
W is work done and t is time
The unit of work done is Joules and that of time is seconds.
Power, P = J/s
We know that, J/s = watts
Hence, the unit of power is watts.
How many moles of N2O5 are needed
to produce 7.90 g of NO2?
Answer:
0.085 moles of N₂O₅ are needed
Explanation:
Given data:
Mass of NO₂ produces = 7.90 g
Moles of N₂O₅ needed = ?
Solution:
2N₂O₅ → 4NO₂ + O₂
Number of moles of NO₂ produced :
Number of moles = mass/ molar mass
Number of moles = 7.90 g/ 46 g/mol
Number of moles = 0.17 mol
now we will compare the moles of NO₂ with N₂O₅.
NO₂ : N₂O₅
4 : 2
0.17 : 2/4×0.17 = 0.085 mol
Thus, 0.085 moles of N₂O₅ are needed.
Suggest reasons for and against the inclusion of hydrogen in the main group of the periodic table
Answer:
See explanation
Explanation:
Hydrogen has only one valence electron. Sometimes, hydrogen is included as part of group 1 or 17 in the periodic table. Is this correct? Well, the answer to this question is not so straight forward!
Let us remember that hydrogen forms a univalent positive ion H^+ just like the group 1 elements, but it also forms a univalent negative ion H^- just like group 17 elements. Also, hydrogen is a gas and forms a molecular diatomic compound just like group 17 elements. This is not the case with other group 1 elements. We can see that hydrogen is chemically and physically dissimilar to other group 1 elements hence one can logically argue against its inclusion in group 1. Also, it is not a halogen, so we can also argue against its inclusion in group 17.
However, it is convenient to include hydrogen in the main groups 1 or 17 when discussing its chemical properties in order to make it easier to assimilate. If we place hydrogen in group 1, we can understand that it forms univalent positive ions. Similarly, if we place it in group 17, we understand that it forms univalent negative ions.
Most times hydrogen is just written separately at the top right corner of the periodic table and not as a member of any group because of the issues outlined above.
Hydrogen is placed in the main group of the periodic table since it has only one electron in it and it also behaves like alkali metal properties.
Hydrogen atom:Hydrogen forms a univalent positive ion [tex]H^+[/tex]group 1 elements, but it also forms a univalent negative ion [tex]H^-[/tex]group 17 elements. Also, hydrogen is a gas and forms a molecular diatomic compound just like group 17 elements.
This is not the case with other group 1 elements. We can see that hydrogen is chemically and physically dissimilar to other group 1 elements hence one can logically argue against its inclusion in group 1. Also, it is not a halogen, so we can also argue against its inclusion in group 17.
If we place hydrogen in group 1, we can understand that it forms univalent positive ions and if it is placed in halogen group it will form univalent negative ion.
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In a balanced chemical equation the mass of the reactants and products are equal.
True
False
A balanced chemical equation obeys the law of conservation of mass. In a balanced chemical equation the mass of the reactants and products are equal. The correct option is true.
What is a balanced chemical equation?A chemical equation in which the number of atoms of reactants and products on both sides of the equation are equal is defined as the balanced chemical equation. The numbers which are used to balance the chemical equation are called coefficients. They are found in front of formulas.
According to law of conservation of mass, mass can neither be created nor be destroyed. But it can be transformed from one form to another.
In a balanced chemical equation, the total mass of the reaction remains constant. The mass of the reactants before reaction is equal to the mass of products after reaction.
Thus the given statement is true.
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Calculate the pH for the following buffer solutions with steps.
1. 7.4862 grams of acetic acid and 10.4695 grams of sodium acetate are dissolved in enough deionized water to make 250.0 mL of solution.
2. 11.8115 grams of trimethylamine and 18.7088 grams of trimethylammonium chloride are dissolved in enough deionized water to make 500.0 mL of solution.
Thank You:)
Answer:
Answer is shown on the paper :D
Explanation:
Remember to follow sig-figs.
Do you think chemistry has something to do with your life?In not less than 5 sentences but not more than 10 sentences try to identify situations during the day in which chemistry somehow played a part
Answer:
Chemistry can be applicable in many aspects which are
i) At school, through getting knowledge you can assess different aspect of chemistry, eg production of Chemicals.
ii) At hospital, also chemistry can be applicable in hospital because most of medicine and other materials are made up from chemistry application.
iii) Agriculture, through agricultural materials it simply because you can get more efficient through planted by using manures and fertilizer which are made up from chemistry application.
27. The compound having only primary hydrogen atoms is ( ).
(A) isobutene
(B) 2,3-dimethylbutene
(C) cyclohexane
(D) propyne
Answer:
The correct answer is - (a) isobutene.
Explanation:
A 1° or primary hydrogen atom is one that is bonded to a 1° carbon atom; a 2° hydrogen atom is one that is connected to a 2° carbon atom; In isobutene only among all the all option having only primary hydrogen atoms. rest have secondary or teritary hydrogen atoms in them
C1∘H3≡CH: (only 1∘ hydrogen atoms)
If the positive end of a water molecule were to encounter the surface shown above, what might happen to the surface’s negative charges? Explain your reasoning.
Answer:
The negative charges of the surface will be attracted to the positive ends of the water molecule
Explanation:
A water molecule is a polar molecule. This means that the two ends of a water molecule are oppositely charged with one end being positive and the other end being negative.
When the positive end of a water molecule encounters a surface as shown in the attachment, where positive and negative charges are evenly distributed at rest, with the negative charges free to move, the negative charges will be attracted to the positive end of the water molecule due to the principle of electrostatics which states that unlike charges attract, while like charges repel. This means that negative and positive charges are attracted to each other while positive and positive or negative and negative charges are repelled from each other. Therefore, the water molecule will adhere to the surface because of the attraction between opposite charges.
The unlike charges will attract as expected based on the laws of electrostatics.
According to the laws of electrostatics, like charges repel while unlike charges attract. We are told in the question that water is a polar molecule with a positive and a negative end.
If the positive end of water dipole approaches the negative charges on the surface, the unlike charges will attract as expected based on the laws of electrostatics.
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Write a word or phrase beginning with each letter of the word GOLD that describes the properties of these gold coins
Periodic table is divided into three metals, non metals and metalloids. The metals are kept on the left side of the periodic table. Gold is a metal which exist in d block.
What is metal ?
Metals are those elements which is hard, conduct electricity, ductile, lustrous and malleable.
The properties of gold are:
1.Gold have free electrons that's why they can conduct electricity
2. Since atoms in Gold are very closely packed in a definite crystal so gold is solid. It is not brittle that is it can not be broken down easily
3. Gold does not react with water easily.
4.Gold is denser than water hence it sink in water.
Gold is a transition element. Gold is found in d block of periodic table. Its symbol is Au.
Therefore, Gold is a metal which exist in d block.
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1. A dry food product is contained in a 1 cm x 4 cm x 3 cm box using a polymer film to protect the oxygen sensitivity of the product. The concentration gradient across the film is defined by the oxygen concentration in air (0.01164 kg/m3) and 0.244 kg/m3 within the package. The oxygen diffusivity for the polymer film is 3 x 10-16 m2/s. Estimate a- the allowable flux of oxygen into the package (in kg O2/s), and b- the film thickness needed, to ensure a product shelf life of 10 months. The shelf life of the product is established as the time when oxidation reactions within the product have used 0.5 mol of oxygen.
Answer:
total is 20.8
Explanation:
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The diagram below shows the main parts of the respiratory system.
Nose
ch
3
Lungs
Diaphragm
Which of these correctly names the parts of the respiratory system numbered 1
through 5 in the diagram above?
A 1. larynx, 2. pharynx, 3. trachea, 4. bronchi, 5. alveoli
B 1. pharynx, 2. larynx, 3. trachea, 4. bronchi, 5. alveoli
C 1. pharynx, 2. larynx, 3. bronchi, 4. trachea, 5. alveoli
Answer:
pharynx > larynx>trachea> bronchi>alveoli (so B)
Explanation:
nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange)
Please help I need this done
Answer:
they arent alcohols.
Explanation:
PLEASE HELP WILL GIVE BRAINLEIST ASAP Determine the fraction of an original sample of K-42 that remains unchanged after 24.72 hours.
Answer:
25% or 0.25 or 1/4
Explanation:
don't know which form you need so here you have all 3
good luck :)
SOMEONE HELP WITH THE LAST QUESTION QUESTION 2) HURRY IM IN ZOOM<3
The value of x = 97
The unknown angles : 97°,97°, 107° and 59°
Further explanationOne variable linear equation is an equation that has a variable and the exponent number is one.
Can be stated in the form:
[tex]\large{\boxed{\bold{ax=b}}[/tex]
or
ax + b = c, where a, b, and c are constants, x is a variable
The parallelogram has total angle of 360°.
The value of each of the 4 angles of the parallelogram :
1. x°
2. x°
3. x+10°
4. 59°
The sum of the four angles of this parallelogram is :
[tex]\tt x+x+x+10+59=360[/tex]
So that the mathematical equation becomes (by combining the like terms) :
[tex]\tt 3x+69=360\\\\3x=291\\\\x=97[/tex]
So the value of the four angles (by entering the x value)
1. 97°
2. 97°
3. x+10=97+10=107°
4. 59°
Ammonia will decompose into nitrogen and hydrogen at high temperature. Calculate the pressure equilibrium constant for the decomposition of ammonia at the final temperature of the mixture
Answer:
Kp = P (N₂) . P³ (H₂) / P² (NH₃)
Explanation:
The reaction for the decomposition of ammonia is given by;
2NH₃ (g) ⇌ N₂ (g) + 3H₂ (g)
The pressure equilibrium constant gives the ratio of the pressure of the product over reactants for a reaction that is at equilibrium.
The pressures of the species are raised to the powers of their respective coefficients.
In this reaction;
Products = N₂ (g) + 3H₂ (g)
Reactant = 2 NH₃ (g)
The pressure equilibrium constant (Kp) is given as;
Kp = P (N₂) . P³ (H₂) / P² (NH₃)
Using the balanced equation below,
how many grams of zinc would be
required to produce 9.65 g of zinc
hydroxide?
Zn + 2MnO2 + H20 → Zn(OH)2 + Mn203
Please help I need it for a test
Answer:
Mass = 6.538 g
Explanation:
Given data:
Mass of zinc hydroxide produced = 9.65 g
Mass of zinc required = ?
Solution:
Chemical equation:
Zn + 2MnO₂ + H₂O → Zn(OH)₂ + Mn₂O₃
Number of moles of zinc hydroxide:
Number of moles = mass/molar mass
Number of moles = 9.65 g/ 99.42 g/mol
Number of moles = 0.1 mol
now we will compare the moles of zinc and zinc hydroxide,
Zn(OH)₂ : Zn
1 : 1
0.1 : 0.1
Mass of zinc required:
Mass = number of moles × molar mass
Mass = 0.1 mol × 65.38 g/mol
Mass = 6.538 g
Answer: 6.35
Explanation:
A red laser pointer emits light at a wavelength of 488 nm. If the laser emits 7.5 10–4 J of energy per second in the form of visible radiation, how many photons per second are emitted from the laser?
a)
4.1 10–19 photons/sec
b)
5.4 10–16 photons/sec
c)
8.9 1014 photons/sec
d)
1.8 1015 photons/sec
e)
2.5 1018 photons/sec
The answer to the question, how many photons per second are emitted from the laser is d. 1.84 × 10¹⁵ photons/sec
Since the red laser pointer emits light of wavelength 488 nm, we need to find the energy of each photon from
E = hc/λ where h = Planck's constant = 6.63 × 10⁻³⁴ Js, c = speed of light = 3 × 10⁸ m/s and λ = wavelength of light = 488 nm = 488 × 10⁻⁹ m
Substituting the values of the variables into the equation, we have
E = hc/λ
E = 6.63 × 10⁻³⁴ Js × 3 × 10⁸ m/s ÷ 488 × 10⁻⁹ m
E = 19.89 × 10⁻²⁶ Jm ÷ 488 × 10⁻⁹ m
E = 0.04076 × 10⁻¹⁷ J per photon
E = 4.076 × 10⁻¹⁹ J per photon
Since the laser emits 7.5 × 10⁻⁴ J per second, the number of photons emitted from the laser per second = energy per second/energy per photon
= 7.5 × 10⁻⁴ J per second ÷ 4.076 × 10⁻¹⁹ J per photon
= 1.84 × 10¹⁵ photons/sec
The answer to the question, how many photons per second are emitted from the laser is d. 1.84 × 10¹⁵ photons/sec
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What is the mass of Na2CO3∙10H2O that is needed to make 100 ml of sodium carbonate solution with the mass percentage of Na2CO3∙ equal to 2%? The density of the final solution is equal to 1 g/ml.
first we find the mass of the final solution
we know that
density=mass/volume
we know the density and volume
1=m/100
m=100g
now we calculate the mass ofNa2CO3
2% of 100 is equal with 2g of Na2CO3
NOT A TEST AND I WILL GIVE BRAINLEIST DON'T ANSWER IF YOU DON'T KNOW
Which particles are in the nucleus of an atom? What are their charges?
Which particles orbit the outside of the atom? What is their charge?
Answer:
In the nucleus of an atom ,there are protons & neutrons. Protons have charge of 1.6× 10^-19 C, while neutrons have 0C charges. Electrons orbit outside the atom. Their charge is - 1.6 ×10^-19C
Explanation:
even about the food chain is correct?
Answer:
its C, because the cocunut tree gets energy from the sun and makes it into cocunut that is true
Explanation:
its C, because the cocunut tree gets energy from the sun and makes it into cocunut that is true
The molecules in a solid do not move.
True
False
Answer:
True
Explanation:
Solid molecules don't move.
Molecule of a solid are tightly packed there is no space between them so there is no movement of the molecule.
The particles (atoms or molecules) are attracted to each other. The particles (atoms or molecules) vibrate but do not move past one another. The solid retains its shape.
true
Look at picture and answer will mark brainliest.
Answer:
A
Explanation:
A chemist determines by measurements that moles of bromine liquid participate in a chemical reaction. Calculate the mass of bromine liquid that participates. Be sure your answer has the correct number of significant digits.
Answer:
This question is incomplete as it lacks the number of moles of Bromine. The complete part is as follows: 0.0900 moles of bromine liquid participate in a chemical reaction.
The answer is 7.191g
Explanation:
The number of moles in a substance can be calculated thus;
moles = mass/molar mass
Atomic mass of Bromine = 79.9g/mol
According to the question, the chemist determines by measurements that 0.0900 moles of bromine liquid participate in a chemical reaction. To calculate the mass of bromine liquid that participates, we say;
Mass = moles × molar mass
Mass = 0.0900 × 79.9
Mass = 7.191g
Therefore, 7.191g of Bromine will participate in the chemical reaction.
Which property of gases is explained by the process of diffusion?
A.
their ability to compress under high temperature
B.
their ability to expand under low temperature
C.
their ability to expand under pressure
D
their ability to fill the available volume of a container
Answer:
The appropriate alternative is "Option D".
Explanation:
Diffusion would be a random or physical phenomenon that corresponds to that same transfer budget of molecules from some kind of highly concentrated area to something like a lower one. The substance which diffuses may be strong, liquids, and gaseous. Correspondingly, the framework where certain diffusion happens can however be amongst the three aspects of sustainability.All those other options aren't relevant to the situation in question. So the above alternative becomes the right one.