What is the difference of mapping the periodic table and introducing the periodic table?


  • Réponse publiée par: shannel99


    Acid rain describes any form of precipitation that contains high levels of nitric and sulfuric acids. It can also occur in the form of snow, fog, and tiny bits of dry material that settle to Earth. Normal rain is slightly acidic, with a pH of 5.6, while acid rain generally has a pH between 4.2 and 4.4.

    Causes of acid rain:

    1)Rotting vegetation and erupting volcanoes release some chemicals that can cause acid rain, but most acid rain is a product of human activities. The biggest sources are coal-burning power plants, factories, and automobiles.

    2)When humans burn fossil fuels, sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the atmosphere. Those air pollutants react with water, oxygen, and other substances to form airborne sulfuric and nitric acid. Winds may spread these acidic compounds through the atmosphere and over hundreds of miles. When acid rain reaches Earth, it flows across the surface in runoff water, enters water systems, and sinks into the soil.

    Effects of acid rain:

    1) Sulphur dioxide and nitrogen oxides are not primary greenhouse gases that contribute to global warming, one of the main effects of climate change; in fact, sulfur dioxide has a cooling effect on the atmosphere. But nitrogen oxides contribute to the formation of ground-level ozone, a major pollutant that can be harmful to people. Both gases cause environmental and health concerns because they can spread easily via air pollution and acid rain.

    2) Acid rain has many ecological effects, especially on lakes, streams, wetlands, and other aquatic environments. Acid rain makes such waters more acidic, which results in more aluminum absorption from soil, which is carried into lakes and streams. That combination makes waters toxic to crayfish, clams, fish, and other aquatic animals. (Learn more about the effects of water pollution.)

    What can be done?

    1)The only way to fight acid rain is by curbing the release of the pollutants that cause it. This means burning fewer fossil fuels and setting air-quality standards.

    2)In the U.S., the Clean Air Act of 1990 targeted acid rain, putting in place pollution limits that helped cut sulfur dioxide emissions 88 percent between 1990 and 2017. Air-quality standards have also driven U.S. emissions of nitrogen dioxide down 50 percent in the same time period. These trends have helped red spruce forests in New England and some fish populations, for example, recover from acid rain damage. But recovery takes time, and soils in the northeastern U.S. and eastern Canada have only recently shown signs of stabilizing nutrients.

  • Réponse publiée par: jbaningzzz



    91 % because it is stronger

  • Réponse publiée par: homersoncanceranguiu

    wd separating rice from water seperating pebbles and sand cleaning the pool sieve to collect the fallen leaves or dirt

  • Réponse publiée par: jemuelpogi

    Gay-Lussac's gas law is a special case of the ideal gas law where the volume of the gas is held constant. When the volume is held constant, the pressure exerted by a gas is directly proportional to the absolute temperature of the gas. These example problems use Gay-Lussac's law to find the pressure of gas in a heated container as well as the temperature you would need to change the pressure of gas in a container.

    Gay-Lussac's Law Example

    A 20-liter cylinder contains 6 atmospheres (atm) of gas at 27 C. What would the pressure of the gas be if the gas was heated to 77 C?

    To solve the problem, just work through the following steps:

    The cylinder's volume remains unchanged while the gas is heated so Gay-Lussac's gas law applies. Gay-Lussac's gas law can be expressed as:

    Pi/Ti = Pf/Tf


    Pi and Ti are the initial pressure and absolute temperatures

    Pf and Tf are the final pressure and absolute temperature

    First, convert the temperatures to absolute temperatures.

    Ti = 27 C = 27 + 273 K = 300 K

    Tf = 77 C = 77 + 273 K = 350 K

    Use these values in Gay-Lussac's equation and solve for Pf.

    Pf = PiTf/Ti

    Pf = (6 atm)(350K)/(300 K)

    Pf = 7 atm

    The answer you derive would be:

    The pressure will increase to 7 atm after heating the gas from 27 C to 77 C.

    Another Example

    See if you understand the concept by solving another problem: Find the temperature in Celsius needed to change the pressure of 10.0 liters of a gas that has a pressure of 97.0 kPa at 25 C to standard pressure. Standard pressure is 101.325 kPa.

    First, convert 25 C to Kelvin (298K).  Remember that the Kelvin temperature scale is an absolute temperature scale based on the definition that the volume of a gas at constant (low) pressure is directly proportional to the temperature and that 100 degrees separate the freezing and boiling points of water.

    Insert the numbers into the equation to get:

    97.0 kPa / 298 K = 101.325 kPa / x

    solving for x:

    x = (101.325 kPa)(298 K)/(97.0 kPa)

    x = 311.3 K

    Subtract 273 to get the answer in Celsius.

    x = 38.3 C

    Tips and Warnings

    Keep these points in mind when solving a Gay-Lussac's law problem:

    The volume and quantity of gas are held constant.

    If the temperature of the gas increases, pressure increases.

    If temperature decreases, pressure decreases.

    Temperature is a measure of the kinetic energy of gas molecules. At a low temperature, the molecules are moving more slowly and will hit the wall of a containerless frequently. As temperature increases so do the motion of the molecules. They strike the walls of the container more often, which is seen as an increase in pressure.  

    The direct relationship only applies if the temperature is given in Kelvin. The most common mistakes students make working this type of problem is forgetting to convert to Kelvin or else doing the conversion incorrectly. The other error is neglecting significant figures in the answer. Use the smallest number of significant figures given in the problem.

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What is the difference of mapping the periodic table and introducing the periodic table?...