Answer:
a quantity chosen as a standard in terms of which other quantities may be expressed.
Explanation:
Explanation:
Unit is a standard physical quantity defined and adopted by convention,with other quantity of same kind.
What happens when The vapour obtained by dropping conc. H2SO4 in a mixture of KI and MnO2 is treated with hypo solution
The reaction between H2SO4 in a mixture of KI and MnO2 yields iodine which reacts with hypo solution by titration and the iodine is decolorized.
Iodine is decolorized.
The first reaction stated in the question occurs as follows;
2 KI (aq) + 2 H2SO4 (aq) + MnO2 (s) → MnSO4 (aq) + K2SO4 (aq) + I2 (s) + 2 H2O (l)
The reaction here is the formation of iodine from MnO2 and KI in the presence of dropwise H2SO4.
Hypo is the common name of sodium thio-sulphate or sodium hypo-sulfite.
The equation of the titration reaction is;
2Na2S2O3 + I2→ Na2S4O6 + 2NaI
When this reaction takes place, iodine is decolorized due to its reduction to I^-.
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9. a) Name salt that can be prepared by precipitation
I think its the substances that sublimes
functions of idiophones
is any musical instrument that creates sound primarily by the vibration of the instrument itself without the use of air flow
A 1.732 g sample of iron is heated in air. It oxidizes to form a product with a mass of 2.205 g.
What is the empirical formula of the product?
Answer:
A 1.732 g sample of iron is heated in air. It oxidizes to form a product with a mass of 2.205 g. What is the empirical formula of the product? FeO 4. Caffeine is made of 49.48% carbon, 5.19% hydrogen, 28.85% nitrogen, and 16.48% oxygen by mass.
Explanation:
The empirical formula of the product formed by the reaction of iron and oxygen is FeO.
Let's consider the following generic chemical equation:
Fe + O₂ ⇄ FexOy
According to the law of conservation of mass, the sum of the masses of the reactants is equal to the sum of the masses of the products. The mass of O₂ that reacted, and remains in the oxide is:
[tex]mFe + mO_2 = mFexOy\\mO_2 = mFexOy - mFe = 2.205 g - 1.732 g = 0.473 g[/tex]
The oxide has 1.732 g of Fe and 0.473 g of oxygen and a total mass of 2.205 g. To determine the empirical formula, we need to calculate the percent composition.
[tex]\%Fe = \frac{mFe}{mFexOy} \times 100 \% = \frac{1.732 g}{2.205 g} \times 100 \% = 78.55\%[/tex]
[tex]\%O = \frac{mO}{mFexOy} \times 100 \% = \frac{0.473 g}{2.205 g} \times 100 \% = 21.45\%[/tex]
Now, we will divide each percentage by the atomic mass of the element.
[tex]Fe: 78.55/55.85 = 1.406\\O: 21.45/16.00 = 1.340[/tex]
Finally, we divide both numbers by the smallest one.
[tex]Fe: 1.406/1.340 \approx 1 \\O: 1.340/1.340 = 1[/tex]
The empirical formula of the product is FeO.
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Which atom is abundant on earth
Answer:
Oxygen
Explanation:
Oxygen is abundant on earth
an atom contains positive protons and negative electrons. Why atom is electrically neutral.
Answer:
atom is electrically neutral because
the no.of protons is equal to no.of
electrons.
Therefore the negative charge and
positive charge cancels out.
Which of the following olosaic structures represents a poskwe 9 protons, 10 mentions and 10 elections 12 protons, 1814 neutrons and 12 elections 12 protons, 12 neutrons and 10 elections
Answer:
migraine
Explanation:
d
Fe + HNO₃ -> Fe(NO₃)2 + H₂
If you start with 4.5 moles of aluminum and 6.5 moles of copper chloride to make aluminum chloride and copper, what is the limiting reagent?
2Al + 3CuCl -> 2AlCl3 + 3Cu
Answer:
The limiting reagent is CuCl
Explanation:
The initial number of moles of aluminum, Al = 4.5 moles
The number of moles of copper, Cu = 6.5 moles
The given chemical reaction is presented as follows;
2Al + 3CuCl → 2AlCl₃ + 3Cu
Therefore, we have, 2 moles of aluminum combine with 3 moles of CuCl produces 2 moles of AlCl₃ and 3 moles of Cu
1 mole of Al will combine with (3/2) moles of CuCl,
Therefore, 4.5 moles of Al will combine with (4.5 × (3/2) = 6.75) 6.75 moles of CuCl
Given that the number of moles of CuCl present is only 6.5 moles which is less than the 6.75 moles required to combine with the 4.5 moles, the 6.5 moles of CuCl limits the amount of AlCl₃ and Cu produced, and therefore the CuCl is the limiting reagent.
Convert the following absolute temperatures to centigrade.
i) 0 K
ii) 298 K
iii) 323 K
iv) 423 K
SHOW STEP BY STEP
Answer:
0 K
[tex]{ - \bf{273 \degree C}}[/tex]
298 K
[tex]{ \tt{ = 298 - 273}} \\ = { \bf{25 \degree C }}[/tex]
323 K
[tex]{ \tt{ = 323 - 273}} \\ = { \bf{50 \degree C}}[/tex]
423 K
[tex]{ \tt{ = 423 - 273}} \\ = { \bf{150 \degree C}}[/tex]
1.T=[£+273]
=273
It is because kelvin temperature is absolute zero.
What does the reducing agent do in a redox reaction? (A.P.E.X)
Answer:
The reducing agent donates electron to the oxidizing agent and gets oxidized itself
Explanation:
In an oxidation-reduction reaction, also known as REDOX reaction, one of the reactants is called OXIDIZING AGENT while the other is called REDUCING AGENT. The reducing agent is called so because it reduces another substance in the reaction.
It reduces another atom/ion by donating electrons to that atom, hence, getting oxidized itself in the process. For example, in the following reaction:
H2 + F2 → 2HF
Fluorine is getting oxidized from -2 to 0 by donating electrons to H and reducing it from +2 to 0.
Answer:
Reduces another atom
Explanation:
:)
A molecular orbital is a region of space in a covalent species where electrons are likely to be found. The combination of two atomic orbitals always forms two molecular orbitals; the bonding molecular orbital, which is _____ in energy, and the antibonding molecular orbital, which is _____ in energy, than the original atomic orbitals.
Answer:
bonding molecular orbital is lower in energy
antibonding molecular orbital is higher in energy
Explanation:
Electrons in bonding molecular orbitals help to hold the positively charged nuclei together, and they are always lower in energy than the original atomic orbitals.
Electrons in antibonding molecular orbitals are primarily located outside the internuclear region, leading to increased repulsions between the positively charged nuclei. They are always higher in energy than the parent atomic orbitals.
True or false, The four units that must always be used when using the ideal gas are 44.0 liters
Answer:
for volume only liters can be used
Explanation:
What is the molarity of a solution made by dissolving 8.60 g of a solid with a
molar mass of 21.50 g/mol in 280.0 mL of solution.
Answer:
1.43 M
Explanation:
We'll begin by calculating the number of mole of the solid. This can be obtained as follow:
Mass of solid = 8.60 g
Molar mass of solid = 21.50 g/mol
Mole of solid =?
Mole = mass / molar mass
Mole of solid = 8.60 / 21.50
Mole of solid = 0.4 mole
Next, we shall convert 280 mL to litre (L). This can be obtained as follow:
1000 mL = 1 L
Therefore,
280 mL = 280 mL × 1 L / 1000 mL
280 mL = 0.28 L
Thus, 280 mL is equivalent to 0.28 L.
Finally, we shall determine the molarity of the solution. This can be obtained as illustrated below:
Mole of solid = 0.4 mole
Volume = 0.28 L
Molarity =?
Molarity = mole / Volume
Molarity = 0.4 / 0.28
Molarity = 1.43 M
Thus, the molarity of the solution is 1.43 M.
A certain volume of gas S takes 180 secs to diffuse through a porous plug. An equal amount of gas Q takes 240 secs to diffuse the same plug. Calculate the molar mass of gas Q if the molar mass of gas S is 18.
Answer:
31.98g/mol
Explanation:
Using Graham's law of diffusion, which states that the rate of diffusion of a gas is inversely proportional to the square root of its molecular mass (M). Rate of diffusion = volume/time.
Since both gas S and Q have equal volumes, we can calculate molecular mass of gas Q as follows:
tQ/tS = √mQ /√mS
Where:
tQ = time of diffusion of gas Q
tS = time of diffusion for gas S
mQ = molar mass of gas Q
mS = molar mass of gas S
According to the information provided in this question;
tQ = 240s
tS = 180s
mQ = ?
mS = 18g/mol
Using tQ/tS = √mQ /√mS
240/180 = √mQ / √18
1.333 = √mQ / √18
Square both sides
1.333² = mQ/18
1.78 = mQ/18
mQ = 18 × 1.78
mQ = 31.98g/mol
Molar mass of Q = 31.98g/mol
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Argon is an element in the last column of the periodic table. What is its highest energy sublevel?
A.D
OB.
OC.P
DS
The highest energy sublevel of argon will be p.
ArgonArgon has an atomic number of 18.
Thus, the electron configuration of argon will be [tex]1s^2, 2 s^2, 2 p^6, 3 s^2, 3 p^6[/tex]
The ascending order of energy for the sublevel orbitals is s, p, d, and f.
Therefore, the highest energy sublevel of argon is p.
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The highest energy sublevel in the element argon is p.
What is the periodic table?The periodic table is an arrangement of atoms according to their order of increasing atomic numbers. Now we know that there are 18 groups in the periodic table and argon belongs to group 18.
The electron configuration of argon is; 1s2 2s2 2p6 3s2 3p6. Thus, the highest energy sublevel in the element argon is p.
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Classify each area of study as being a branch of science or not a branch of science. If you're unsure, take your best guess.
Drag each tile to the correct location.
SCIENCE
NOT SCIENCE
astronomy
astrology
biology
chemistry
geology
physics
theology
Answer: Science : Chemistry, astronomy , biology , physics , biology ,geology. Notscience : Astrology and theology
Explanation: Astrology and theology are non scientific areas of study.
True or false..
(A) Burning of magnesium ribbon is physical change
Answer:
False because it is chemical change
What is the hydronium ion concentration of a solution with a pOH of 7.20?
A - 1.56 × 10^−6 M
B - 1.79 × 10^−6 M
C - 1.58 × 10^−7 M
D - 2.78 × 10^−7 M
I think the correct answer is C, can anyone confirm this?
Answer:
C - 1.58 × 10^−7 M
Explanation:
The hydroxide ion concentration can be found from the pOH by the reverse mathematical operation employed to find the pOH. [OH-] = 10-pOH or [OH-] = antilog ( - pOH) Page 2 Example: What is the hydroxide ion concentration in a solution that has a pOH of 5.70? On a calculator calculate 10-5.70, or "inverse" log (- 5.70).
The concentration of hydronium ion C) - 1.58 × 10^−7 M
The concentration of hydronium ionif pOH is 7.20 than pH = 14-7.20∴pH=6.80
The hydroxide ion concentration can be found from the pOH by the reverse
How do you calculate concentration from pH?To calculate the pH of an aqueous solution we need to know the concentration of the hydronium ion in moles per liter (molarity).
The pH is then calculated using the expression:
pH = - log [H3O+]
-log[6.80]
- 1.58 × 10^−7 M
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Calculate the amount (in moles) of gas which occupies 250cm³ at STP
Answer:
0.01
Explanation:
volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.
Iron and chlorine form an ionic compound whose formula is FeCl3. The name of this compound is __________. Group of answer choices iron chlorine iron (III) chloride moniron trichloride iron (III) trichloride ferric trichloride
Answer:
Iron and chlorine form an ionic compound whose formula is FeCl3. The name of this compound is iron (III) chloride or iron trichloride.
Explanation:
Iron (III) chloride or Iron trichloride is also known as ferric chloride, it is a common compound of iron in the +3 oxidation state. The anhydrous compound is a crystalline solid with a melting point of 307.6 °C.
The classification of an acid or base as weak or strong is based uponGroup of answer choicesthe solubility of the acid or basethe extent of dissociation of the acid or basethe concentration of acid or base in solutionmore than one response is correct
Answer: the extent of dissociation of the acid or base
Explanation:
When an acid or base dissociates, it means that they go back to their original ions in order to be able to react with the atoms in the solution they dissociated in.
Stronger acids and bases are able to almost completely dissociate in a solution which is why they are able to react with the atoms in the solution very easily. The strength of an acid or base is therefore measured by how much dissociation they can manage in a solution.
Although tom was a poor student, he studied very well
PLZ HELP ME WITH MY WORK
Answer:High density
Explanation:
The metal doesn't remains gas at room tempreture, it doesn't have brittleness property and it is not poor conductor of electricity .But, it has high density .
Hope, it would be correct.
Vitamin C is a water-soluble vitamin, so your body doesn't store it. You have to get the required amount from your diet (citrus fruits are a great source!), or you could take a daily vitamin C supplement pill. Vitamin C is ascorbic acid, so to determine how much vitamin C (acid) has been placed in each pill, you could do an acid-base titration. One vitamin C pill was dissolved in water and titrated to an endpoint by 16.00 mL of a 0.447 M solution of NaOH. How many grams of ascorbic acid were there in the pill? (MW of ascorbic acid is 176.1 /mol). Explain and show your work.
Answer:
Mass of ascorbic acid in the pill = 7.152 x 176.1/1000 = 1.26 g
Explanation:
The mass of ascorbic acid in the pill would be,
1.26 g
Now,
Moles of ascorbic acid = Moles of NaOH = 0.447 M x 16 ml = 7.152 mmol
Mass of ascorbic acid in the pill = 7.152 x 176.1/1000 = 1.26 g
Which star has the highest surface temperature
A. blue star
B. yellow star
C. white star
D. red star
Answer:
The blue star is the hottest star.
Explanation:
Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K
Temperature and kinetic energy have, what type of relationship
Answer:Calor y temperatura son dos conceptos diferentes pero estrechamente relacionados. Observa que tienen diferentes unidades: la temperatura típicamente tiene unidades de grados Celsius (^\circ\text C
∘
Cdegrees, start text, C, end text) o Kelvin (\text KKstart text, K, end text), y el calor tiene unidades de energía, joules (\text JJstart text, J, end text). La temperatura es una medida de la energía cinética promedio de los átomos o moléculas en el sistema. Las moléculas de agua en una taza de café caliente tienen una mayor energía cinética promedio que las moléculas de agua en una taza de té helado, lo que también significa que están moviéndose a una velocidad más alta. La temperatura también es una propiedad intensiva. Esto significa que no depende de qué tanta cantidad tengas de una sustancia (¡siempre y cuando esté toda a la misma temperatura!). Por esta razón, los químicos pueden utilizar el punto de fusión para poder identificar una sustancia pura: la temperatura a la cual se derrite es una propiedad de la sustancia que no depende de la masa de una muestra.
A nivel atómico, las moléculas en cada objeto están constantemente en movimiento y chocando entre sí. Cada vez que chocan, pueden transferir energía cinética. Cuando dos sistemas están en contacto, se va a transferir calor del sistema más caliente al más frío por medio de choques moleculares. La energía térmica va a fluir en esa dirección hasta que los dos objetos están a la misma temperatura. Cuando esto ocurre, decimos que están en equilibrio térmico.
Explanation:
Al calor a veces se le llama una magnitud de proceso, porque está definido en el contexto de un proceso por el cual se puede transferir energía. No decimos que una taza de café contiene calor, pero podemos hablar del calor transferido de la taza de café caliente a tu mano. El calor también es una propiedad extensiva, así que el cambio de temperatura que resulta al transferir calor a un sistema depende de cuántas moléculas hay en el sistema.
Three Balanced equations for Ammonium salt+Alkali=Salt+water+carbon dioxide
Answer:
NH₄Cl (aq) + NaOH (aq) -> NaCl (aq) + H₂O (l) + NH₃ (g)
(NH₄)₂CO₃ (aq) + 2KOH (aq) -> K₂CO₃ (aq) + 2H₂O (l) + 2NH₃(g)
NH₄NO₃ (aq) + LiOH (aq) -> LiNO₃ (aq) + H₂O (l) + NH₃ (g)
Explanation:
The gas liberated when an alkali reacts with an ammonium salt is NH₃ (ammonia), not CO₂.
Help! Can somebody explain the answer and how they got it?
"Write the equation for the first ionization of potassium."
Answer:
K°(g)* + 419 Kj/mole => K⁺(g) + e⁻
Explanation:
1st ionization step for potassium is the ionization of the 4s¹ electron. This requires 419 Kj/mole energy (endothermic). The reaction equation is ...
K°(g)* + 419 Kj/mole => K⁺(g) + e⁻
*note: Ionization of group IA metals requires they be in gas phase. That is, as shown by the Born-Haber Cycle** for formation of ionic compounds ...
K°(s) + 89.24 Kj/mole => K°(g); then ...
K°(g) + 419 Kj/mole => K⁺(g).
**Recommend review of Born-Haber cycle for formation of ionic compounds.
PLZ HELP ME WITH MY WORK
What is a compound?
A substance that is made from two different metals
B. A substance that cannot be broken into simpler substances
C. A substance that is made using a chemical reaction
D. A substance that can be separated by physical means
Answer:
C.
Explanation:
Answer A is incorrect because a compound doesn't have to be made with only metals.
Answer B is incorrect because that is actually the definition of a pure element.
Answer C is correct because to make a compound, there has to be a chemical reaction where bonds are formed and an entirely new substance is created.
Answer D is incorrect because compounds cannot be separated by physical means.
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