Urgent please help
A.Ca
B. CaO
C.CO

Answer:

A chemical reaction that has a positive ΔH is said to be endothermic , while a chemical reaction that has a negative ΔH is said to be exothermic . What does it mean if the ΔH of a process is positive? It means that the system in which the chemical reaction is occurring is gaining energy.

Answer:

migraine

Explanation:

d

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.

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.

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.

Answer:

Cl

Explanation:

n for Mg=m:Mm

=65.8:24

=2.74mol

n for Cl=m:Mm

=45.7:70

=0.65mol

According to the number of moles we can say that the limiting reagent is Cl as it has few moles.

Limiting agents are the reactant that determines the amount of the product in a reaction. In the reaction between magnesium and hydrochloric acid, the limiting reagent is HCl.

A limiting reagent is a substance that restricts or determines the amount of product formation in a reaction. They are the reactants with less number of moles and get consumed in the reaction before the other reactant.

The reaction between magnesium and hydrochloric acid is given by,

Mg(s) + 2HCl(aq)  → MgCl₂(aq) + H2(g)

Here, 1 mole of Mg and 2 moles of HCl are required to produce 1 mole of magnesium chloride.

The moles of Mg,

= 65.8 g ÷ 24.305

= 2.707 mol

And, moles of HCl

= 45.7 g ÷ 36.458

= 1.253 mol

The stoichiometric ratio Mg : HCl = 1:2

Hence, Mg = 2.707 ÷ 1 = 2.707  and HCl = 1.253 ÷ 2 = 0.6265

Therefore, HCl is the limiting reagent.

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Answer:

9.97×10⁻⁴ atm

Explanation:

Applying,

PV = nRT............... Equation 1

Where P = pressure, V = volume, n = number of moles of air, R = molar gas constant, T = Temperature.

make P the subject of the equation

P = nRT/V............ Equation 2

From the question,

Given: V = (11×12×8) ft³ = 1056 ft³ = (1056×28.3168) = 29902.5 L, T = 25°C = (25+273) = 298 K, n = 35.41/29 = 1.22 mole

Constant: R = 0.082 atm.L/K.mol

Substitute these values into equation 2

P = 1.22×0.082×298/29902.5

P = 9.97×10⁻⁴ atm

Answer:

YES!

Explanation:

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.

I don't know I am having the same problem

Answer:

solubility of salt at 10 degree Celsius is 20 how does it what does it means what happens if the temperature of saturated solution is increased

Explanation:

solubility of salt at 10 degree Celsius is 20 how does it what does it means what happens if the temperature of saturated solution is increased

Answer:

for volume only liters can be used

Explanation:

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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Answer:

C. ATP.

Explanation:

During the process of aerobic cellular respiration, energy is said to be released in three main stages: glycolysis, Krebs cycle and oxidative phosphorylation (electron transport chain). The electron transport chain produces the most energy and it involves the transfer of electrons through series of complex proteins.

As the electrons move through the individual complexes, energy is lost to form a proton gradient (H+). The proton gradient powers the synthesis of ATP from ADP as catalyzed by ATP synthase.

Answer: Science : Chemistry, astronomy , biology , physics , biology ,geology. Notscience : Astrology and theology

Explanation: Astrology and theology are non scientific areas of study.

Answer:

100 cm³

Explanation:

Hi there!

Subtract:

400 cm³ - 300 cm³

= 100 cm³

Therefore, the volume of the object is 100 cm³.

I hope this helps!

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.

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.

The highest energy sublevel of argon will be p.

Argon 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.

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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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.

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.

The steps involved in the manufacture of sulphuric acid by contact process:

(1) Sulphur (or iron pyrites) are burnt in air to form sulphur dioxide.

  S+O2→SO24FeS2+11O2→2Fe2O3+8SO2

(2) Catalytic oxidation of sulphur dioxide to sulphur trioxide.

  2SO2+O2V2O52SO3ΔrHo=−196.6kJ

The reaction is reversible and exothermic.

(3) Sulphur trioxide is dissolved in 98% sulphuric acid to form oleum (fuming sulphuric acid). 

  SO3+H2SO4→H2S2O7

(4) Oleum is diluted with water to form sulphuric acid of desired concentration.

    H2S2O7+H2O→2H2SO4

            and

Manufacture of H2SO4 by contact process involves three steps:

1. Burning of sulphur in air to generate SO2.

2. Conversion of SO2 to SO3 by oxidation with air in the presence of 

Answer:

Nuclear energy.

Explanation:

It's the energy that holds protons and neutrons ( nucleons ) together, hence holds the nucleus as one.

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.

Answer:

False because it is chemical change

Answer:

1.48 moles of SeCl6 are needed

Explanation:

Based on the reaction:

SeCl6 + O2 → SeO2 + 3Cl2

1 mole of SeCl6 reacts producing 3 moles of Cl2.

To solve this question we need to use the conversion factor:

1mol SeCl6 = 3mol Cl2

As we want to produce 4.45 moles of Cl2, we need:

4.45 mol Cl2 * (1mol SeCl6 / 3mol Cl2) =

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

                                     ∴pH=6.80

The hydroxide ion concentration can be found from the pOH by the reverse

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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Answer:

A

Explanation:

the nervous system helps parts of the body communicate.through nerves.

I hope this helps

Answer:

a white crystalline substance that gives seawater it characteristics of taste