Answer:

**Answer:**

**1.62 g**

**Explanation:**

Given that:

Concentration of HCN = 0.119 M

Assuming the ka 4.00 × 10⁻¹⁰

The pKa of HCN (hydrocyanic acid) = -log (Ka)

= - log ( 4.00 × 10⁻¹⁰)

= 9.398

pH of buffer = 8.809

Using Henderson Hasselbach equation:

[CN^-] = 0.2576[HCN]

[CN^-] = 0.2756 (0.119) L

[CN^-] = 0.033 M

∴

The amount of NaCN (sodium cyanide) is calculated as follows:

**= 1.62 g**

In the United States, volume of irrigation water is usually expressed in acre-feet. One acre-foot is a volume of water sufficient to cover 1 acre of land to a depth of 1 ft (640 acres = 1 mi2, 1 mi = 5280 ft). The principal lake in the California Water Project is Lake Oroville, whose water storage capacity is listed as 3.54 x 106 acre-feet. Express the volume of Lake Oroville in (a) cubic feet, (b) cubic meters, and (c) US gallons.

If the heat of combustion of carbon monoxide (CO) is −283.0 kJmole, how many grams of carbon monoxide must combust in order to release 2,500.kJ of energy?

Identify the catalyst-containing systems below as homogeneous or heterogeneous. Catalysts (4 items) (Drag and drop into the appropriate area below) NO(g) for the oxidation of SO2(g) to SO3(g)KI(aq) for the decomposition of H2O2(aq)H2(g) bonded to a metal surfacePd(s) coating that converts noxious gas to less harmful gases

Impulse is ___ momentum. A. only a decrease in B. a change in c. not related to D. only an increase in

The Heat of vaporization for NH3= 1360 J/g. Calculate the quantity of heat energy (in kJ)needed to completely boil a 155 gram sample at its boiling pointgeneral formula

If the heat of combustion of carbon monoxide (CO) is −283.0 kJmole, how many grams of carbon monoxide must combust in order to release 2,500.kJ of energy?

Identify the catalyst-containing systems below as homogeneous or heterogeneous. Catalysts (4 items) (Drag and drop into the appropriate area below) NO(g) for the oxidation of SO2(g) to SO3(g)KI(aq) for the decomposition of H2O2(aq)H2(g) bonded to a metal surfacePd(s) coating that converts noxious gas to less harmful gases

Impulse is ___ momentum. A. only a decrease in B. a change in c. not related to D. only an increase in

The Heat of vaporization for NH3= 1360 J/g. Calculate the quantity of heat energy (in kJ)needed to completely boil a 155 gram sample at its boiling pointgeneral formula

**Answer:**

1.4 g H₂O

**Explanation:**

In a reaction, the reactants are usually not present in exact* stoichiometric amounts*, that is,

Zn+2 (aq) + 2e− → Zn(s) Eo=−0.763V

Answer the following questions about this cell.

Write a balanced equation for the half-reaction that happens at the cathode.

Write a balanced equation for the half-reaction that happens at the anode.

Write a balanced equation for the overall reaction that powers the cell. Be sure the reaction is spontaneous as written. Do you have enough information to calculate the cell voltage under standard conditions

**Answer:**** The reaction is spontaneous and there is not enough information to calculate the cell voltage.**

**Explanation:**

The substance having highest positive reduction potential will always get reduced and will undergo reduction reaction.

Oxidation reaction occurs at anode and reduction reaction occurs at cathode.

**For a:**

**The half reactions for the cell occurring at cathode follows:**

**For b:**

**The half reactions for the cell occurring at anode follows:**

**( × 2)**

**For c:**

**The balanced equation for the overall reaction of the cell follows:**

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

**Relationship between standard Gibbs free energy and standard electrode potential follows:**

For a reaction to be spontaneous, the standard electrode potential must be positive.

**To calculate the of the reaction, we use the equation:**

**Putting values in above equation, we get:**

As, the standard electrode potential of the cell is coming out to be positive, the reaction is spontaneous in nature.

**To calculate the EMF of the cell, we use the Nernst equation, which is:**

As, the concentrations and partial pressures are not given. So, there is not enough information to calculate the cell voltage.

**Hence, the reaction is spontaneous and there is not enough information to calculate the cell voltage.**

**Answer:**

**400 Joules**

**Explanation:**

From the question,

The total kinetic energy of the water balling when hits the ground is given as

K.E = 1/2mv².................. Equation 1

Where K.E = Kinetic Energy of water ballon, m = mass of water balloon, v = velocity of water ballon

Given: m = 2 kilograms, v = 20 meters/second.

Substitute these values into equation 1

K.E = (2×20²)/2

K.E = 2×400/2

K.E = 400 Joules

**Answer: Cao2 **

**Explanation: the reason for this is because the chemical reactions on both sides should be equal and since the O has a 2 the O should have 2 on the other equation.**

Answer

Density = 7.87g/cm^3

Explanation:

Density is the ratio of mass of the given object to the volume of the object, in this question iron is the given object, then we make use of atomic number of iron

Given:

Length= 287pm = 287*10^-10cm

Atomic mass of Fe= 56.0u

Z=2(for body centered cubic unit cell)

Avogadro number (N 0)=6.022× 10^23

Density= ZM/a^3 × N

Where

Z= body centered cubic unit cell

Then substitute

N= Avogadro's number

a=Length

Density = (2× 56)/(287*10^-10cm)^3 × (6.022 × 10^23)

Density = 7.87g/cm^3

The density of iron in a body-centered cubic unit cell can be calculated using the mass and volume of the unit cell.

The density of iron can be calculated using the formula: density = mass/volume. To determine the mass of the unit cell, we need to know the molar mass of iron and the number of atoms in the unit cell. The molar mass of iron is 55.845 g/mol, and there are two iron atoms in the body-centered cubic unit cell of iron. The volume of the unit cell can be calculated using the formula: volume = (edge length)^3.

Putting these values into the formula, we get:

density = (2 * 55.845 g/mol) / ((287 pm)^3)

Converting the edge length to meters (1 pm = 1e-12 m) and calculating, we find that the density of iron is approximately 7.86 g/cm³.

#SPJ11

**Answer:**

A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.