How do we get Hydrogen for Fuel?

Hydrogen is found in stars, like the sun, and even in our bodies.

The United States imports around half of the oil it uses. That means we buy much of our oil from other countries. And, the price of oil has increased over time. In July 2011, oil cost up to $99 per barrel, up from $76 per barrel five years before.  Economist expect the price fluctuation of oil to continue.  Also, fossil fuels are non-renewable, meaning that once they are used, they are gone forever.

Researchers are looking for new sources of energy so we can use less fossil fuel. Homes and businesses already use electricity harnessed from the sun, wind, water, and biomass. However, powering a vehicle needs a different solution. The power source needs to be portable, and it needs to allow the vehicle to go at least 300 miles before recharging or refueling.

Hydrogen could be one of the solutions. Since there are so many sources of hydrogen, more hydrogen fuel can be created as it is needed.

By-products: Pure hydrogen is already being produced in many manufacturing plants. Petroleum refining and chemical production create hydrogen as a by-product. Fossil fuels, such as natural gas, can be reformed to produce hydrogen gas.

Electrolysis: Renewable energy sources such as windmill farms, solar collectors or hydroelectric generators can supply electricity for electrolysis. Electrolysis is used to split water molecules into pure hydrogen and oxygen.

Nuclear power: Nuclear energy can produce large amounts of hydrogen. Nuclear power does not give off greenhouse gases or other harmful air emissions. The nuclear reaction used to make hydrogen does not use carbon-based materials, a common source of pollutants. Nuclear power does create radioactive waste from spent fuel rods.

New research: The U.S. Department of Energy has used photosynthesis to create pure hydrogen. In an experiment, plant enzymes were able to split water molecules, creating the hydrogen. In another experiment, glucose from plants was used. Glucose can also come from waste, like paper mill sludge, cheese whey and wood waste.

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Kimia Dasar I.

Unsur

Penjelasan struktur tabel periodik

Jumlah kulit elektron yang dimiliki sebuah atom menentukan periode atom tersebut. Setiap kulit memiliki beberapa subkulit, yang terisi menurut urutan berikut ini, seiring dengan bertambahnya nomor atom:

1s

2s 2p

3s 3p

4s 3d 4p

5s 4d 5p

6s 4f 5d 6p

7s 5f 6d 7p

8s 5g 6f 7d 8p

...

Berdasarkan hal inilah struktur tabel disusun. Karena elektron terluar menentukan sifat kimia suatu unsur, unsur-unsur yang segolongan umumnya mempunyai sifat kimia yang mirip. Unsur-unsur segolongan yang berdekatan mempunyai sifat fisika yang mirip, meskipun massa mereka jauh berbeda. Unsur-unsur seperiode yang berdekatan mempunyai massa yang hampir sama, tetapi sifat yang berbeda.

Sebagai contoh, dalam periode kedua, yang berdekatan dengan Nitrogen (N) adalah Karbon (C) dan Oksigen (O). Meskipun massa unsur-unsur tersebut hampir sama (massanya hanya selisih beberapa satuan massa atom), mereka mempunyai sifat yang jauh berbeda, sebagaimana bisa dilihat dengan melihat alotrop mereka: oksigen diatomik adalah gasyang dapat terbakar, nitrogen diatomik adalah gas yang tak dapat terbakar, dan karbon adalah zat padat yang dapat terbakar (ya, berlian pun dapat terbakar!).

Sebaliknya, yang berdekatan dengan unsur Klorin (Cl) di tabel periodik, dalam golongan Halogen, adalah Fluorin (F) dan Bromin (Br). Meskipun massa unsur-unsur tersebut jauh berbeda, alotropnya mempunyai sifat yang sangat mirip: Semuanya bersifat sangat korosif (yakni mudah bercampur dengan logam membentuk garam logam halida); klorin dan fluorin adalah gas, sementara bromin adalah cairan bertitik didih yang rendah; sedikitnya, klorin dan bromin sangat berwarna.