12) Balance the following chemical equation: Zn + H3PO4 Zn3(PO4)2 + H2

Which is the best reason that a geologist might carry a small dropper bottle filled with hydrochloric acid when doing fieldwork?

natta225 [31]

Answer:

C is the correct answer

Explanation:

to test for the presence of carbonate minerals in a rock

7 0

3 years ago

1. A light bulb is filled with 3.54 g of argon at 25 C and 725 mmHg. What is

Ugo [173]

Answer: The volume of given gas is 2.27 L.

Explanation:

Given: Mass = 3.54 g

Temperature = $25^{o}C$ = (25 + 273) K = 298 K

Pressure = 725 mm Hg (1 mm Hg = 0.00131579) = 0.95 atm

As moles is the mass of substance divided by its molar mass.

So, moles of argon (molar mass = 40 g/mol) is as follows.

$Moles = \frac{mass}{molar mass}\\= \frac{3.54 g}{40 g/mol}\\= 0.0885 mol$

Formula used to calculate the volume of given gas is as follows.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

$PV = nRT\\0.95 atm \times V = 0.0885 mol \times 0.0821 L atm/mol K \times 298 K\\V = 2.27 L$

Thus, we can conclude that the volume of given gas is 2.27 L.

3 0

3 years ago

What is the wavelength of spectral line resulted from the electron transition from n=3 to n=2 in a hydrogen atom.

MakcuM [25]

Answer:

$\lambda=6.56x10^{-7}m$

Explanation:

Hello there!

In this case, it possible to use the Rydberg equation in order to calculate the wavelength for this transition from n=3 to n=2 as shown below:

$\frac{1}{\lambda} =R_H(\frac{1}{n_f^2}-\frac{1}{n_i^2} )$

Thus, we plug in the corresponding energy levels and the Rydberg constant to obtain:

$\frac{1}{\lambda} =10973731.6m^{-1}(\frac{1}{2^2}-\frac{1}{3^2} )\\\\\frac{1}{\lambda} =1524129.4m^{-1}\\\\\lambda=\frac{1}{1524129.4m^{-1}} \\\\\lambda=6.56x10^{-7}m$

Best regards!

5 0

3 years ago

105° S T X= what does x equal

pav-90 [236]

Answer:

kgcvgvfjkjkvfjk

Explanation:

7 0

3 years ago

There are three main parts to any dissolution which result in an energy change, either endothermic or exothermic. Consider the d

valkas [14]

Answer:

The dissolution of sodium chloride involves three steps. During the process energy changes occur in:

1. breaking apart the hydrogen bonds between water molecules,

2. breaking apart the electrostatic bonds between sodium and chloride ions, and

3. when bonds are formed between water molecules and aqueous ions in solution.

Since the energy used to break apart the hydrogen bonds between water molecules and the energy used to break apart the electrostatic bonds between sodium and chloride ions, is greater than the energy released when bonds are formed between water molecules and aqueous ions in solution, the dissolution of sodium chloride is endothermic.

Explanation:

The heat of solution or enthalpy of solution/dissolution, is the enthalpy change that occurs with the dissolution of a solute in a solvent at constant pressure, resulting in infinite dilution. Its unit is kJ/mol for reactions taking place under standard conditions (298.15 K and 1 atm).

The process of dissolution occurs in three energy-dependent steps:

1. The breaking of bonds within the solute. For example, electrostatic forces of attraction between two oppositely-charged ions. This process is endothermic.

2. The endothermic process of breaking of intermolecular forces within the solvent, e.g. hydrogen bonds in water.

3. The exothermic process of the formation of new solute-solvent bonds in solution.

The sum of the energies involved in these three steps gives the enthalpy of dissolution of a solute. The overall process of dissolution can either endothermic or exothermic depending on the amount of energy used or released in breaking and making bonds. If more energy is released in making than is used in breaking bonds, it is exothermic. However, if more energy is used in breaking bonds than is released in making bonds, dissolution is then endothermic.

For example, considering the dissolution of sodium chloride. During the process the energy used to break apart the hydrogen bonds between water molecules and the energy used to break apart the electrostatic bonds between sodium and chloride ions, is greater than the energy released when bonds are formed between water molecules and aqueous ions in solution. Therefore, the dissolution of sodium chloride is endothermic.

3 0

3 years ago