Answer:
B. distance light travels in a year
got it on edge :)
The statement which accurately and best describes a light-year is the total distance which light travels in a complete year
What is velocity of light?Velocity of light can simply be defined as that fundamental constant that represents the speed of electromagnetic radiation in a vacuum.
The velocity of light = 2.9979 × 10^10cm/s
So therefore, the statement which accurately and best describes a light-year is the distance which light travels in a complete year
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Which condition must be met in order for an equation to be balanced? The elements in the reactants are the same as the elements in the products. There are fewer elements in the reactants than there are in the products. The number of atoms in the reactants is greater than the number of atoms in the products. The number of atoms in the reactants equals the number of atoms in the products.
Answer:
The number of atoms in the reactants equals the number of atoms in the products.
Explanation:
In every chemical reaction equation there are two sides; the reactants sides and the products side. The reactants side shows the species that combine to form the products. On both sides of the reaction equation, chemical species are found to be composed of atoms.
The major principle in balancing of chemical reaction equations is that the number of atoms of each element in the reactants side must be equal to the number of atoms of the same element on the products side. Once this condition is achieved, we can now say that the chemical equation is balanced.
Answer:
Answer D: The number of atoms in the reactants equals the number of atoms in the products.
Explanation:
Had the answer plus doing the quiz right now and got it right 100%
Energy from a reaction was determined to be 3870 J using a water calorimeter, when burning 9.00 grams of H2. What is the total enthalpy of the reaction?
Answer:
860 J / mol
Explanation:
Enthalpy = Energy / no. of moles
no. of moles = mass / molar mass
Take the atomic mass of H = 1.0,
molar mass of H2 = 1.0 x 2
= 2.0
no. of moles of H2 = 9.00/2
= 4.5 mol
Hence,
Enthalpy = 3870 / 4.5
=860 J / mol
Which best describes a neutralization
reaction?
A) a reaction between an acid and a base
B) a reaction between two acids
C) a reaction between a base and a salt
D) a reaction between two salts
Explanation:
The Answer is a reaction between two acids
Ammonia is produced when a mixture of of ammonium chloride and substance C is heated. What is substance X?
How many significant figures are there in 6.07x10^-15?
Answer:
3
Explanation:
6.07 has 3 digits and all are significant
PLEASE HELP ME
One method to produce nitrogen in the lab is to react ammonia with copper (II) oxide: NH3(g) + CuO(s) ---> Cu(s) + H2O(l) + N2(g). After using 40.0 grams of NH3, 15.5 grams of N2 are produced. What is the percent yield of nitrogen in the reaction?
Answer:47.05% is the percent yield of nitrogen in the reaction.
Explanation:
heoretical yield of nitrogen gas = x
Moles of ammonia =
According to reaction,2 moles of ammonia gives 1 mol of nitrogen gas.
Then 2.3529 mol of ammonia will give:
of nitrogen gas
Mass of 1.1764 moles of nitrogen gas,x = 1.1764 mol × 28 g/mol=32.94 g
Experiential yield of nitrogen gas = 15.5 g
Percentage yield:
hope that help
47.05% is the percent yield of nitrogen in the reaction.
What statement describes the cause for sibling rivalry between both brothers? The older son shared his fears about providing financial support for the family after graduating. The sons challenged each other by competing for the highest grade point average that year. The younger son expressed feelings about his parents showing favoritism to his older sibling. The sons disagreed over the handling of family tasks once the younger son heads off to college
Answer:
c
Explanation:
you took the test on edge
The statement describes the cause for sibling rivalry between both brothers is The younger son expressed feelings about his parents showing favoritism to his older sibling. Hence , Option (C) is correct.
What is Sibling rivalry ?Sibling rivalry is the jealousy, competition and fighting between brothers and sisters.
It is a concern for almost all parents of two or more kids.
Problems often start right after the birth of the second child.
Sibling rivalry usually continues throughout childhood and can be very frustrating and stressful to parents.
Therefore, The statement describes the cause for sibling rivalry between both brothers is The younger son expressed feelings about his parents showing favoritism to his older sibling. Hence , Option (C) is correct.
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write chemical equation for the following decomposition reactions. Aluminum oxide(s) decomposes when electricity is passed through it.
Answer:
2Al2O3 (l) ---> 4Al (l) + 3O2 (g)
Explanation:
The reaction is the electrolysis of aluminium oxide. It decomposes aluminium oxide (Al2O3) into aluminium metal (Al) and Oxygen (O2). In this process, aluminium oxide is molten (liquid state) so that ions can move to complete the electricity circuit.
Al2O3 (l) ---> Al (l) + O2 (g)
Balance the equation:
2Al2O3 (l) ---> 4Al (l) + 3O2 (g)
Which property would cesium most likely have?
Answer: The property that cesium most likely would have is being ductile (able to be deformed without losing toughness) due it being a very soft, alkali metal which has a very low melting point of 83.3 °F or 28.5 °C
Answer:
The answer is B. Ductile.
Explanation: Cesium belongs to a category of metals. They are often silver, fairly soft, and very ductile. The answer is right on edge 2020.
Question 7 of 25
What is an energy level?
A. The total energy possessed by all the electrons of an atom
B. The energy contained within the nucleus of an atom
C. The energy required to remove an electron from its nucleus
D. The energy possessed by an electron at a set distance from the
nucleus
SUBMIT
Answer:
d)the energy possessed by an electron at a set distance from the nucleus
show bond formation in magnesium chloride
mg has a 2 in its valence shell
it will become mgcl2
. . . .
: Cl -------- Mg ------ Cl :
. . . .
If he wants to model a longitudinal wave that carries more energy, how should he move the end of the spring?
Answer:
they won
Explanation:
What's the valency of sulphur for SO2?
Answer:
The valency of sulphur in SO2 is 4.
Hope this helps..
[tex]good \: luck[/tex]
144g of KCl dissolved in 1000cm3of water at 90oC. Calculate the solubility of KCl at this temperature. (K=39, Cl=35.5, 1dm3=1000cm3).
Answer:
The solubility of KCl is 1.93 mol/dm³
Explanation:
The information given are;
The mass of the potassium chloride, KCl = 144 g
The volume of the water solvent = 1000 cm³ = 1 dm³
The temperature of the solvent = 90 °C
The atomic mass of potassium, K = 39 u
The atomic mass of chlorine, Cl = 35.5 u
The number of moles of potassium in one mole of potassium chloride, KCl = 1 mole
The number of moles of chlorine in one mole of potassium chloride, KCl = 1 mole
The molar mass of the potassium chloride = 39 + 35.5 = 74.5 g/mol
The number of moles, n, of potassium chloride, KCl in 144 g of potassium chloride, KCl is given as follows
n = Mass/(Molar mass) = 144/74.5 = 1.93 moles
1.93 moles will dissolve in 1 dm³
Therefore, the solubility of KCl is 1.93 mol/dm³.
Na-23 has 12 neutrons. What is it’s atomic number?
Answer:
11
Explanation:
Data obtained from the question include:
Mass number = 23
Neutron = 12
Atomic number =.?
Next, we shall determine the number of protons present in the element.
This can be achieved by doing the following:
Mass number = Proton + Neutron
Mass number = 23
Neutron = 12
Proton =...?
Mass number = Proton + Neutron
23 = Proton + 12
Collect like terms
Proton = 23 – 12
Proton = 11
The atomic number of an element is equal to the proton number.
Atomic number = proton number
Proton number = 11
Atomic number = proton = 11
Therefore, the atomic number is 11.
answer the question briefly: How can atom collapse and why are atoms stable?
The nuclei of atoms become unstable when the repelling forces of the protons cannot be balanced by the number of neutrons in the nucleus. It then re-arranges itself randomly to a more stable configuration by emitting any of a series of particles. During radioactive decay, an atom does not collapse.
Since an atom is mostly empty space - that is it’s nucleus is relatively distant from the electron shells so, in the presence of extreme forces such as gravity inthe collapse of a large star, the inward pressures on the atom overcome the natural balance of the atomic structure and the ‘empty space’ disappears as nuclei are mashed together by the intense pressures and a neutron star is formed. Under even more external pressure, even the neutron star can collapse to form a black hole.
Name a Solid, Liquid, and a Gas. Solid: Liquid: Gas:
Answer:
Gas - Steam
Solid - Rock
Liquid - Juice
Answer:
Solid: Ice
Liquid: Water
Gas: Steam or Water vapor
Explanation:
This is a common example to answer your question. Some other examples are:
-most metals(ex: iron, tin, copper, gold) These are solids
-milk, juice, hot chocalate, any soda drink These are liquids
-hydrogen, helium, carbon dioxide, oxygen These are gases
Hope this helps!
The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. product concentration; one-half; structure of the substrate enzyme concentration; one-half; temperature optimum of the enzyme substrate concentration; one-half; the affinity of the substrate-enzyme interaction substrate concentration; one-fourth; pH optimum of the enzyme
Answer:
substrate concentration; one-half; the affinity of the substrate-enzyme interaction
Explanation:
The Michaelis constant, Km, refers to the substrate concentration at which a reaction proceeds at one-half of the maximum velocity. This constant most accurately reflects the affinity of the substrate-enzyme interaction.
what particle determines the name of the element?
Answer:
The protons determine the name of an element and also atomic number because its the same as protons.
A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. The titration curve above was obtained with pH at equivalence point of around 8. The unknown compound is ________.
Answer:
Weak acid
Explanation:
A titration curve is a graphical description of the change in pH of the solution in the conical flask as the reagent is added from the burette. A titration curve can be plotted for the different kinds of acid and base titrations. The volume of the titrant is always plotted as the independent variable and the pH of the solution as the dependent variable. The equivalence point is read off from the titration curve. A titration curve is very important because it shows the pH at various points during the titration.
A weak acid/strong base titration leads to an equivalence point above 7. From the question, we were told that the pH at equivalence point lies around 8. Hence the unknown substance must be a weak acid.
Which of the following observations indicates that atoms of all elements contain small, negatively charged particles? Alpha particles are repelled by cathode rays of elements. Cathode rays are deflected towards a positively charged rod. A particular frequency of light is produced by a gas in an excited state. Certain areas of the atom called orbitals contain all the charged particles.
Answer:
The correct option is;
Cathode rays are deflected towards a positively charged rod
Explanation:
Cathode rays are beam of electrons emitted from the cathode in a vacuum tube and moving towards the anode, due to the difference in the voltage between the electrodes
The discovery of the electrons was through the proof by Thomson that cathode rays were a negatively charged, previously unknown particle, which was to become known as the electron.
Answer:
Cathode rays are deflected towards a positively charged rod
Explanation:
i took the exam this is correct
Identify the type of reaction in the following and define each of them. (i) Carbohydrates are broken down to form glucose. (ii) Tarnishing of copper. (iii) Heating of ferric oxide with aluminium powder. (iv) Blue colour of copper sulphate solution disappears when zinc dust is added to it. (v) Dilute sulphuric acid is adeed to sodium hydroxide solution .
Answer:
(i) hydrolysis; (ii) combination; (iii) single replacement;
(iv) single replacement; (v) double replacement
Explanation:
(i) Carbohydrates are broken down to form glucose
Carbohydrates must react with water to form glucose.
For example,
C₆H₁₁O₅-O-C₆H₁₁O₆ + H-O-H ⟶ 2C₆H₁₂O₆
maltose glucose
This is a hydrolysis reaction — the reaction of a compound in which a molecule of water breaks one or more bonds to form new substances.
The reaction is not a decomposition (a reaction in which a compound breaks down into two or more simpler substances), because two different molecules are involved.
(ii) Tarnishing of copper.
Cu + S ⟶ CuS
This is a combination or synthesis reaction — in which two or more substances combine to form a single new substance.
(iii) Heating of ferric oxide with aluminium powder
Fe₂O₃ + 2Al ⟶ Al₂O₃ + 2Fe
This is a single displacement or single replacement reaction — in which one element replaces another element in a compound.
Here, Al is replacing Fe in its oxide.
(iv) Blue colour of copper sulphate solution disappears when zinc dust is added to it
CuSO₄ + Zn ⟶ ZnSO₄ + Cu
This is a single displacement or single replacement reaction.
Here, Zn is replacing Cu in its sulfate.
(v) Dilute sulfuric acid is added to sodium hydroxide solution
H₂SO₄ + 2NaOH ⟶ Na₂SO₄ + 2H₂O
2H⁺, SO₄²⁻ + 2Na⁺OH⁻ ⟶ 2Na⁺, SO₄²⁻ + 2H-OH
This is a double displacement or double replacement reaction — in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.
The Na⁺ ions are replacing the H⁺ ions in the sulfuric, forming sodium sulfate and water,
D Serum Levels Of 4 Mcg/mL, Calculate The Dose, In Milligrams, For A 120-lb Patient That May Be Expected To Result In A Blood Serum Gentamicin Level Of 4.5 Mcg/mL. This problem has been solved! See the answer If the administration of gentamicin at a dose of 1.75 mg/kg is determined to result in peak blood serum levels of 4 mcg/mL, calculate the dose, in milligrams, for a 120-lb patient that may be expected to result in a blood serum gentamicin level of 4.5 mcg/mL.
Answer:
The patient requires a dose of 107.2 mg of gentamicin
Explanation:
A dosage of 1.75 mg per Kilogram body weight results in blood serum levels of 4.5 mcg/mL
This means that; 1.75 mg/ kg = 4.0 mcg/mL
Therefore, dosage of gentamicin in mg/kg that will result in 4.5 mcg/mL blood serum level = (1.75 mg/Kg * 4.5 mcg/mL) / 4.0 mcg/mL
Dosageof gentamicin = 1.97 mg/Kg
1-lb = 0.453592 Kg
Weight of 120-lb patient in Kg = 120 * 0.453592 = 54.43 Kg
Dose in mg required by patient = 1.97 mg/Kg * 54.43 Kg = 107.2 mg
Therefore, the 120-lb patient requires a dose of 107.2 mg of gentamicin to result in a blood serum level of 4.5 mcg/mL
Suppose you carry out a titration involving 3.00 molar HCl and an unknown concentration of KOH. To bring the reaction to its end point, you add 35.3 milliliters of HCl to 105.0 milliliters of KOH. What is the concentration of the KOH solution?
Answer: The concentration of the KOH solution is 1.01 M
Explanation:
According to neutralization law:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1[/tex] = basicity of [tex]HCl[/tex] = 1
[tex]n_2[/tex] = acidity of KOH = 1
[tex]M_1[/tex] = concentration of HCl = 3.00 M
[tex]M_2[/tex] = concentration of KOH = ?
[tex]V_1[/tex] = volume of HCl = 35.3 ml
[tex]V_2[/tex] = volume of KOH = 105.0 ml
Putting the values we get:
[tex]1\times 3.00\times 35.3=1\times M_2\times 105.0[/tex]
[tex]M_2=1.01[/tex]
Thus the concentration of the KOH solution is 1.01 M
30cm^3 of a dilute solution of Ca(OH)2 required 11 cm^3 of 0.06 mol/dm^. Hcl for complete neutralization. Calculate the concentration of the Ca(OH)^2 solution in mol/dm^3 and g/dm^3
Answer: Thus concentration of [tex]Ca(OH)_2[/tex] in [tex]mol/dm^3[/tex] is 0.011 and in [tex]g/dm^3[/tex] is 0.814
Explanation:
To calculate the concentration of [tex]Ca(OH)_2[/tex], we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]HCl[/tex]
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is [tex]Ca(OH)_2[/tex]
We are given:
[tex]n_1=1\\M_1=0.06mol/dm^3\\V_1=11cm^3=0.011dm^3\\n_2=2\\M_2=?\\V_2=30cm^3=0.030dm^3[/tex] [tex]1cm^3=0.001dm^3[/tex]
Putting values in above equation, we get:
[tex]1\times 0.06mol/dm^3\times 0.011dm^3=2\times M_2\times 0.030dm^3\\\\M_2=0.011mol/dm^3[/tex]
The concentration in [tex]g/dm^3[/tex] is [tex]0.011mol/dm^3\times 74g/mol=0.814g/dm^3[/tex]
Thus concentration of [tex]Ca(OH)_2[/tex] is [tex]0.011mol/dm^3[/tex] and [tex]0.814g/dm^3[/tex]
Answer:
d
Explanation:
d
calculate the mass of sodium sulphate required to prepare its 20%of solution in 100 g ofwater
Answer:
25 g
Explanation:
Mass percent implies the mass of solute dissolved in a solution
Mass percent = mass of solute/mass of solute + mass of solvent × 100/1
Since mass percent concentration= 20%
Mass of solvent = 100g
Let mass of solute = x
Hence;
20 = x/x +100 ×100/1
20/100= x/x + 100
0.2 = x/x + 100
0.2(x + 100) = x
0.2x + 20 = x
20 = x - 0.2x
20 = 0.8x
x= 20/0.8
x= 25 g
A student has a piece of aluminum metal what is the most reasonable assumption a student can make about the metal
Answer:
- It could be stretched into a thin wire.Explanation:
As per the question, the most rational claim that the student can make about the aluminum metal is that 'it could be stretched into a thin wire' without breaking which shows its ductility. It is one of the most significant characteristics of a metal. Metals can conduct electricity in any state and not only when melted. Thus, option A is wrong. Options C and D are incorrect as metals neither have the same shape always nor do they break on hitting with a hammer. Therefore, option E is the correct answer.
Answer:
Yes, the other person is correct; the answer is E. It could be stretched into a thin wire.
Explanation:
Here is why it is NOT B:
"A briskly burning wood fire is plenty hot enough to melt aluminum. If it's just smoldering (like a lot of campfires) it won't create enough heat to melt aluminum."
Therefore, CAMPFIRES are not likely to melt aluminum if it is thrown in. Aluminum's melting point is 1,221 ° F. Typical campfires are about 900 ° F.
You're Welcome
~Kicho [nm68]
12. Classify the following as conduction, convection or radiation. a. A steel mug kept near a stove becomes hot after some time. b. The metal handlebars of a bicycle are colder than plastic hand grips. c. Some people get sunburn when they go out in the sun for a long time. d. The paper kept above a candle flame starts burning after some time.
A - convection
B - conduction
C - radiation
D - convection
What letter represents the enthalpy of reaction?
Answer:
Option D. T
Explanation:
Enthalpy change (ΔH) is simply the difference between the heat content of the product (Hp) and the heat content of the reactant (Hr). Mathematically, it is expressed as:
Enthalpy change (ΔH) = Heat of product (Hp) – heat of reactant (Hr)
ΔH = Hp – Hr
From the diagram given above, the difference between the heat content of product and the heat content of reactant is T.
Therefore, the enthalpy change of the reaction is T.
Period, group and atomic number of the elements that have the following electrical configurations: 1s2 2s2 2p3 1s2 2s2 2p6 3s2 1s2 2s2 2p5
Answer:
If you follow the periodic table and its orbitals, you'll see that the element that has the electron configuration of 1s²2s²2p³ is Nitrogen. It's period, group, and atomic number are 2, 15, and 7 respectively. The other 2 are Neon, who's period, group, and atomic number are 2, 18, and 10 and the last one is Fluorine, who's period, group, and atomic number are 2, 17, and 9.