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4 years ago

Qualitatively estimate the relative melting points for each of the solids, and rank them in decreasing order.

Chemistry

1 answer:

Ostrovityanka [42]4 years ago

6 0

Answer:

Graphite> sodium chloride> solid ammonia

Explanation:

Melting points of solids has a lot to do with the nature of intermolecular forces in the solid. A substance melts when the intermolecular forces holding the crystal lattice has been overcome such that that the crystal structure of the solid just collapses.

Graphite consists of covalently bonded layers of carbon atom which form a giant lattice. The melting point of graphite is very high because of the fact that the strong covalent bonds that hold the carbon atoms together in the layers require a lot of heat energy to break. Grapoghite melts at about 3600°C

Sodium chloride is an ionic compound that melts at about 801°C. The lattice is composed of alternate sodium and chloride ions.

Solid ammonia is held together by much weaker intermolecular interaction hence it has a melting point of about −77.73 °C.

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bearhunter [10]

Answer:

It helps microorganisms grow

Explanation:

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7 0

3 years ago

Consider the following gas phase reaction:

snow_tiger [21]

Answer:

2NO(g) + O2(g) --> 2NO2(g)

now 400 ml of NO × 2 mol of NO2/2 mol of NO

= 400 ml of NO2

now 500 ml of O2 × 2 mol of NO2/1 mol of O2

= 1000 ml of NO2

now 400 ml of NO2 × 1 mol of O2/2 mol of NO

= 200 ml

subtract that from 500 ml of total i.e. 500-200 =300 ml

The total volume of the reaction mixture is 1000 ml -300ml = 700 ml

6 0

3 years ago

When energy is added to a substance at constant volume and pressure, its temperature increases except ________.

Travka [436]

A. When the substance is in its gaseous state.

Explanation:

When a substance is expanding against its constant volume and pressure, its temperature increases except when the substance is in gaseous state and not in liquid or solid state. So the internal energy increase in the system not only increases and maintaining the volume and pressure of the system remains constant in its gaseous phase. In the first law of Thermodynamics, it is used specifically that to especially in the case of gaseous system.

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3 years ago

Calculate the density in g/l of co2 gas at 27 Celsius and 0.500 atm pressure

lesya692 [45]

Answer:

The density of CO₂ gas at 27 Celsius and 0.500 atm is 0.89 $\frac{grams}{L}$

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:

P*V = n*R*T Equation (A)

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.

Density allows you to measure the amount of mass in a given volume of a substance. So density is defined as the quotient between the mass of a body and the volume it occupies:

$density=\frac{mass}{volume}$