Blog Archives

MOLE redefinition

9/28/2018

The book Chemistry on a Budget contains chemistry labs that are useful with inexpensive, easy to obtain materials.

For the 2018-19 school year, buy a copy of the lab book Chemistry on a Budget. It’s a great resource for your class!

There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report. This way the teacher has the option! Each lab is two pages to allow for one two-sided handout.

A 5-Star Customer Review of Chemistry on a Budget at amazon.com states:
“[S]traight forward, to the point, using household chemicals…this is the lab book for you.
I teach high school chemistry and this is exactly what [I] was looking for. Labs included simple household chemicals that could be easily found. Nice format, easy to follow along procedures, and touches on every topic of our chemistry curriculum.”You can buy this lab book for $23 at amazon.com or lulu.com. It will take 1-2 weeks to get to you -- Order Now. It’s a great resource!

http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

http://www.lulu.com/shop/marjorie-r-heesemann/chemistry-on-a-budget/paperback/product-21217600.html

*Some of you have already purchased my lab book – be sure to check out Page 141 !

“After an extensive consultation with the chemistry community, and following a review and critical evaluation of the literature, IUPAC is recommending a new definition of the mole based on a specified number of elementary entities:
The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.022 140 76 × 1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in mol−1, and is called the Avogadro number.
The new definition is published in the January 2018 issue of IUPAC journal Pure and Applied Chemistry and is readily available online. This IUPAC recommendation includes a discussion and explanatory notes. An earlier Technical Report published in July 2017 included more details and the critical review of the proposed definition of the fundamental chemical quantity ‘amount of substance’ and its unit the ‘mole’.”
https://iupac.org/new-definition-mole-arrived/

“The mole became part of the International System of Units (the SI) in 1971. Currently, it is defined as the amount of substance that contains as many entities as there are in 0.012 kg of carbon-12. But the need to redefine the kilogram has been discussed for decades – not least because of the long-term instability of ‘Le Grand K’, the artefact that defines the kilogram. Following the success of the 1983 definition of the metre, which is based on the speed of light in vacuum, the International Committee for Weights and Measures (CIPM) decided that this is also an opportune time to recast the definitions of all SI base units in terms of the most stable things known to scientists: physical constants.”
https://www.chemistryworld.com/opinion/a-new-definition-of-the-mole/3008663.article

“Iupac’s [International Union of Pure and Applied Chemistry] new definition describes the mole as containing exactly 6.02214076 x 1023 (the Avogadro constant) elementary entities.

Textbooks published from 1971 onwards are likely to define a mole as the mass of substance containing the same number of fundamental units as there are atoms in exactly 12.000 g of 12C.

The new definition stresses that moles are to do with counting entities rather than measuring the mass of a sample of something else.”
https://eic.rsc.org/analysis/a-new-definition-for-the-mole/3008601.article

“Iupac’s new mole definition will be considered by the General Conference on Weights and Measures – the only body that can make changes to the SI – in November this year and, if accepted, will become the official one in May 2019.”
https://www.chemistryworld.com/news/textbooks-need-an-update-after-moles-definition-changed/3008537.article

The celebration of Mole Day on Tuesday, 10/23/2018. Some past blog posts include:
01/10/2014              2nd Entry (Mole Conversions and
                                       Moletown Map)
10/20/2014              Celebrating Mole Day
10/15/2015              Mole Mathematics
10/15/2016              Mole Day is Coming!

Here are several past blog posts that you will find useful for the Beginning of the School Year:

07/06/2014          Decorating Your Classroom
07/13/2014          Chemistry Laboratory Safety
07/20/2014          Classroom Grading Programs
07/27/2014          Classroom Ideas –Daily Announcements
                              and Teacher Websites
08/03/2014          Lab Report Help
08/10/2014          Lab – Reaction in a Bag
03/25/2015          Your School Library
08/27/2015          Outlines for Student Notes
09/17/2015          Multiple Versions of Quizzes and Tests
11/27/2015          Your School Library II
08/28/2016          The First Days of School
01/12/2018          Grading Rubrics for Lab Reports
08/17/2018          Chemistry Using Virtual Reality

For the 2018/2019 school year, buy a copy of the lab book Chemistry on a Budget – it is a great resource! You can examine the labs and decide what you want to use during the school year.

*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.

Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.

Have a great weekend!

0 Comments

gas explosion in boston

9/21/2018

0 Comments

The book Chemistry on a Budget contains chemistry labs that are useful with inexpensive, easy to obtain materials.

For the 2018-19 school year, buy a copy of the lab book Chemistry on a Budget. It’s a great resource for your class!

There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report. This way the teacher has the option! Each lab is two pages to allow for one two-sided handout.

A 5-Star Customer Review of Chemistry on a Budget at amazon.com states:
“[S]traight forward, to the point, using household chemicals…this is the lab book for you.
I teach high school chemistry and this is exactly what [I] was looking for. Labs included simple household chemicals that could be easily found. Nice format, easy to follow along procedures, and touches on every topic of our chemistry curriculum.”
You can buy this lab book for $23 at amazon.com or lulu.com. It will take 1-2 weeks to get to you -- Order Now. It’s a great resource!

http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

http://www.lulu.com/shop/marjorie-r-heesemann/chemistry-on-a-budget/paperback/product-21217600.html

*Some of you have already purchased my lab book – be sure to check out Page 141 !

“Massachusetts Gov. Charlie Baker declared a state of emergency Friday [September 14, 2018] in three towns north of Boston rocked by a string of deadly gas explosions, and he put another utility company in charge of restoration efforts. …

Baker said Eversource would replace Columbia Gas of Massachusetts on the same day he warned stunned residents of the towns that the return to normalcy could take time following blasts Thursday that set homes ablaze, forced evacuations and left one person dead.

Later in the day, the governor said Columbia was ‘simply inadequately prepared’ to effectively manage relief efforts.”
https://www.cnn.com/2018/09/14/us/massachusetts-explosions-fires/index.html

“At least 70 buildings north of Boston, Massachusetts have been set ablaze by what appears to be a ruptured gas line. Authorities are evacuating residents from parts of Lawrence, Andover and North Andover. One person has died.

The residents of the three communities north of Boston, serviced by Columbia Gas, have been ordered to evacuate after a reported gas line rupture triggered a series of violent explosions.

Ironically, perhaps, earlier in the day Columbia Gas issued an announcement that it would begin upgrading its distribution lines in the region.

According to the press release:
For your safety, your gas service will be off during the
installation. We may relocate the gas meter to an
appropriate place outside – at no additional cost to
you. Once our work is completed, we’ll conduct a
natural gas safety inspection outside and inside your
home or business. After a successful inspection, we’ll
relight your appliances.’ ”
https://www.rt.com/usa/438416-boston-gas-explosions-fire/

“At a press conference on Thursday [September 14, 2018], fire investigators suggested that over-pressurization in a gas-delivery main may have caused the blasts. The natural gas supplier for the affected area is Columbia Gas, a subsidiary of NiSource Inc. (NYSE: NI). Columbia serves more than 50,000 customers in the Merrimack Valley including the cities of Andover, North Andover, and Lawrence where the explosions and fires occurred.”
https://247wallst.com/infrastructure/2018/09/14/whats-to-blame-for-boston-area-natural-gas-explosions/

“A federal investigator says there's no evidence to suggest the gas explosions that rocked communities north of Boston were intentional.”
https://www.cbc.ca/news/world/boston-gas-explosion-investigation-no-evidence-intentional-1.4825599

“The Massachusetts natural gas distribution system is one of the oldest in the United States, with the age of some of the piping more than a century old, according to utility company disclosures with the Massachusetts Department of Public Utilities.”
https://www.reuters.com/article/us-massachusetts-explosions/one-dead-a-dozen-injured-in-gas-blasts-in-boston-suburbs-idUSKCN1LU0W6

“U.S. oil and gas pipeline-related deaths jumped to the highest level in seven years in 2017. The 20 fatalities were the most since 2010, when a natural gas pipeline explosion in San Bruno, California, leveled a neighborhood and killed eight people.

In a 2011 letter to PHMSA and others after San Bruno, the National Transportation Safety Board called for a host of improvements to lessen the likelihood of explosions and to reduce the severity of leaks after they happen.”
https://www.bloomberg.com/news/articles/2018-09-14/boston-gas-explosions-highlight-stalled-pipeline-safety-push

“There have been a number of gas-related disasters in recent years. In the San Francisco Bay Area, the San Bruno pipeline explosion on Sept. 9, 2010 killed eight people and wiped out an entire swatch of the suburban enclave located just south of San Francisco. The blast, spawned by a steel natural-gas pipeline that exploded beneath the Crestmoor neighborhood, released a loud roar that sounded to many like an earthquake of a large jet crashing.

This week, the explosions came in a series, setting off fires in dozens of homes in the towns of Lawrence, Andover and North Andover. As gas crews and first-responders tried to shut off gas and electricity to the area, Massachusetts authorities told all residents whose homes are serviced by Columbia Gas in the three communities to flee for safety.

‘This one is unique and unusual,’ said Mark McDonald, president of NatGas Consulting in Boston. ‘It appears to be an over-pressurization of the entire system, which is quite uncommon. ‘ “
https://www.mercurynews.com/2018/09/14/gas-explosions-near-boston-are-just-the-latest-in-a-long-string-of-blasts/

Other related Blog posts include:
01/22/2014      Combustion of a Hydrocarbon
11/25/2014      Predicting Products of a Combustion
                                Reaction (5th Rxn Type)
01/22/2016      Methane Leak in California
01/26/2018      Current Event -- Oil Drill Site Explosion
03/23/2018      Current Event: Chemical Plant Explosion in TX
07/20/2018      Gas Explosion in Wisconsin

Here are several past blog posts that you will find useful for the Beginning of the School Year:

07/06/2014          Decorating Your Classroom
07/13/2014          Chemistry Laboratory Safety
07/20/2014          Classroom Grading Programs
07/27/2014          Classroom Ideas –Daily Announcements
                              and Teacher Websites
08/03/2014          Lab Report Help
08/10/2014          Lab – Reaction in a Bag
03/25/2015          Your School Library
08/27/2015          Outlines for Student Notes
09/17/2015          Multiple Versions of Quizzes and Tests
11/27/2015          Your School Library II
08/28/2016          The First Days of School
01/12/2018          Grading Rubrics for Lab Reports
08/17/2018          Chemistry Using Virtual Reality

Blog posts useful for an Intro to Chemistry unit include:
08/19/2014        Measurement and Significant Figures
08/24/2014        SI System & Scientific Notation
09/02/2014        Dimensional Analysis or
                             The Factor-Label Method
09/12/2014        Density
09/19/2014        Element Symbols & Intro to Chemical
                             Language

For the 2018/2019 school year, buy a copy of the lab book Chemistry on a Budget – it is a great resource! You can examine the labs and decide what you want to use during the school year.

*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.

Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.

Have a great weekend!

0 Comments

High-tech electronics made from autumn leaves

9/14/2018

0 Comments

The book Chemistry on a Budget contains chemistry labs that are useful with inexpensive, easy to obtain materials.

For the 2018-19 school year, buy a copy of the lab book Chemistry on a Budget. It’s a great resource for your class!

There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report. This way the teacher has the option! Each lab is two pages to allow for one two-sided handout.

A 5-Star Customer Review of Chemistry on a Budget at amazon.com states:
“[S]traight forward, to the point, using household chemicals…this is the lab book for you.
I teach high school chemistry and this is exactly what [I] was looking for. Labs included simple household chemicals that could be easily found. Nice format, easy to follow along procedures, and touches on every topic of our chemistry curriculum.”

You can buy this lab book for $23 at amazon.com or lulu.com. It will take 1-2 weeks to get to you -- Order Now. It’s a great resource!

http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

http://www.lulu.com/shop/marjorie-r-heesemann/chemistry-on-a-budget/paperback/product-21217600.html

*Some of you have already purchased my lab book – be sure to check out Page 141 !

“Northern China's roadsides are peppered with deciduous phoenix trees, producing an abundance of fallen leaves in autumn. These leaves are generally burned in the colder season, exacerbating the country's air pollution problem. Investigators in Shandong, China, recently discovered a new method to convert this organic waste matter into a porous carbon material that can be used to produce high-tech electronics.”
https://www.sciencedaily.com/releases/2017/08/170829113813.htm

“Many roads in this part of China are lined with trees of the genus Paulownia, sometimes called phoenix trees. Despite the government’s disapproval, many locals burn the fallen leaves, worsening the country’s notorious air pollution. In Beijing alone, about 2 million tonnes of leaves and other plant waste are burned every year.

Now, Hongfang Ma at the Qilu University of Technology in Jinan and her colleagues have figured out how to turn phoenix tree leaves into organic capacitors. These could be used like batteries to store energy, potentially avoiding some of that air pollution into the bargain.

The process of making organic capacitors does release a little carbon dioxide, but not nearly as much as would be emitted if you let the same quantity of material burn or decay, says Caroline Burgess Clifford at Penn State University. “Any type of use of any waste material is a good thing.”
https://www.newscientist.com/article/2146097-fallen-leaves-could-be-turned-into-devices-that-store-energy/

“The investigators used a multistep, yet simple, process to convert tree leaves into a form that could be incorporated into electrodes as active materials. The dried leaves were first ground into a powder, then heated to 220 degrees Celsius for 12 hours. This produced a powder composed of tiny carbon microspheres. These microspheres were then treated with a solution of potassium hydroxide and heated by increasing the temperature in a series of jumps from 450 to 800 C.

The chemical treatment corrodes the surface of the carbon microspheres, making them extremely porous. The final product, a black carbon powder, has a very high surface area due to the presence of many tiny pores that have been chemically etched on the surface of the microspheres. The high surface area gives the final product its extraordinary electrical properties.

The investigators ran a series of standard electrochemical tests on the porous microspheres to quantify their potential for use in electronic devices. The current-voltage curves for these materials indicate that the substance could make an excellent capacitor. Further tests show that the materials are, in fact, supercapacitors, with specific capacitances of 367 Farads/gram, which are over three times higher than values seen in some graphene supercapacitors .”
http://www.chemeurope.com/en/news/164646/high-tech-electronics-made-from-autumn-leaves.html

“A capacitor is a widely used electrical component that stores energy by holding a charge on two conductors, separated from each other by an insulator. Supercapacitors can typically store 10-100 times as much energy as an ordinary capacitor, and can accept and deliver charges much faster than a typical rechargeable battery. For these reasons, supercapacitive materials hold great promise for a wide variety of energy storage needs, particularly in computer technology and hybrid or electric vehicles.”
https://www.optimistdaily.com/2017/08/china-is-making-high-tech-electronics-from-autumn-leaves/

“The research has been focused on looking for ways to convert waste biomass into porous carbon materials that can be used in energy storage technology. Along with the tree leaves, the team has successfully converted potato waste, corn straw, pine wood, rice straw and other agricultural wastes into carbon electrode materials. The team hopes to improve even further on electrochemical properties of porous carbon materials by optimizing the preparation process and allowing for doping or modification of the raw materials.”
https://electronics360.globalspec.com/article/9676/autumn-leaves-are-a-developing-material-in-high-tech-electronics

This is another attempt to find a way to use a waste material and reduce the amount of CO2 released into the atmosphere rather than letting the leaves simply decompose.

Here are several past blog posts that you will find useful for the Beginning of the School Year:

07/06/2014          Decorating Your Classroom
07/13/2014          Chemistry Laboratory Safety
07/20/2014          Classroom Grading Programs
07/27/2014          Classroom Ideas –Daily Announcements
                              and Teacher Websites
08/03/2014          Lab Report Help
08/10/2014          Lab – Reaction in a Bag
03/25/2015          Your School Library
08/27/2015          Outlines for Student Notes
09/17/2015          Multiple Versions of Quizzes and Tests
11/27/2015          Your School Library II
08/28/2016          The First Days of School
01/12/2018          Grading Rubrics for Lab Reports
08/17/2018          Chemistry Using Virtual Reality

Blog posts useful for an Intro to Chemistry unit include:
08/19/2014          Measurement and Significant Figures
08/24/2014          SI System & Scientific Notation
09/02/2014          Dimensional Analysis or
                                 The Factor-Label Method
09/12/2014          Density
09/19/2014          Element Symbols & Intro to Chemical
                                Language

For the 2018/2019 school year, buy a copy of the lab book Chemistry on a Budget – it is a great resource! You can examine the labs and decide what you want to use during the school year.

*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.

Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.

Have a great weekend!

0 Comments

Airplane air concerns

9/7/2018

0 Comments

not enough oxygen;
not enough outside air to dilute whatever is in the cabin air;
a contaminated air supply; and
exposure to high concentrations of pesticides on selected routes.”

http://www.afacwa.org/aircraft_air_quality

“Most aircraft have strong filter systems. With the exception of some smaller or much older aircraft, airplanes are equipped with True High-Efficiency Particle Filters (True HEPA) or High-Efficiency Particle Filters (HEPA).

These filtration systems then filter and recirculate the air from the cabin and mix it with fresh air. The dirtier a HEPA filter gets, the more efficient it becomes, so it can easily handle the passenger load on a Boeing 747.

Air recirculation happens pretty quickly. The HEPA filtration system can make a complete air change approximately 15 to 30 times per hour, or once every two to four minutes. According to IATA, "HEPA filters are effective at capturing greater than 99 percent of the airborne microbes in the filtered air. Filtered, recirculated air provides higher cabin humidity levels and lower particulate levels than 100 percent outside air systems.

HEPA filters catch most airborne particles, meaning their capture standard is pretty high in term of commercial spaces. A HEPA filter's complete air change is better than most other forms of transportation and office buildings and similar to the standard for hospitals.”
https://www.tripsavvy.com/air-quality-during-your-flight-54164

‘Airplanes take about 50 percent of the air collected in the outtake valves of the passenger compartment and mix it with fresh air from outside that gets heated by the engines. That air is then passed through HEPA filters that sterilize it before it’s reintroduced to the passenger cabin.‘ ”
http://www.nbcnews.com/id/41581445/ns/travel-seasonal_travel/t/does-airplane-air-really-make-you-sick/#.W41n3Lgnbcs

“ ‘Airplane air isn’t as bad as most people envision,’ said Charles Gerba, an environmental microbiologist at the University of Arizona at Tucson. Gerba, also known as Dr. Germ, studies germs and where they congregate and doesn’t worry much about the air quality on airplanes.’On a trip, it’s more likely that the food you eat and the things you touch will make you sick.’ ...

Many passengers mistakenly believe that the air in the cabin that they left the gate with is the air they have to breathe for the rest of the trip. ‘This is not true,’ said Boeing spokesperson Bret Jensen.

He blames low humidity for giving airplane air a bad rap. ‘The overall relative humidity aboard an aluminum airplane is low — around 6 percent — and people become dehydrated on long flights if they don't drink water regularly. This can make people feel different than when they boarded the airplane.’
Modern airplanes do recirculate air, ‘but don’t let that scare you,’ said travel health expert Mark Gendreau, the senior staff physician and vice chair of emergency medicine at Lahey Clinic in Burlington, Mass.

Incidents over the years have occurred when airline passengers claim to have been sickened by the air in the airplane.

For example, on August 2, 2017 in ‘Oklahoma City [, OK] – [m]ultiple people were treated for breathing problems at the Will Rogers World Airport after an unknown odor was reported on a plane. … [A] Jet Blue flight en route to Ft. Lauderdale from California had to stop at the Will Rogers World Airport in Oklahoma City when multiple people on board the plane started having breathing problems due to an unknown odor coming from the back of the plane.
Officials say three crew members and two passengers received medical attention.
The cause of the odor is still being investigated.”
https://kfor.com/2017/08/02/what-we-know-about-unknown-odor-that-caused-breathing-problems-on-plane-that-stopped-at-will-rogers-world-airport/

“The fresh air in a plane’s cabin, known as “bleed air,” is brought in through the engine. Because of this, toxins from the engine oil or hydraulic fluid can seep into the airplane -- either in minute quantities that accumulate over time, or in larger amounts if there’s a leak.

In the latter case, crew members and passengers have suffered from headaches, dizziness, tremors and other neurological symptoms after inhaling the toxins during their flight. Even in small quantities, pilots and flight attendants have suffered long-term neurological symptoms, including tremors, that appear to be the result of long-term exposure to aircraft engine oil contaminants. “
https://articles.mercola.com/sites/articles/archive/2010/04/01/how-airplane-cabin-air-can-get-you-sick.aspx

A starting idea of the year is the definition of Element, Compound and Mixture. Here is the extension of concerns related to air mixtures in airplanes – you may want to develop at Homework assignment from topics in this article.

Here are several past blog posts that you will find useful for the Beginning of the School Year:

07/06/2014          Decorating Your Classroom
07/13/2014          Chemistry Laboratory Safety
07/20/2014          Classroom Grading Programs
07/27/2014          Classroom Ideas –Daily Announcements
                              and Teacher Websites
08/03/2014          Lab Report Help
08/10/2014          Lab – Reaction in a Bag
03/25/2015          Your School Library
08/27/2015          Outlines for Student Notes
09/17/2015          Multiple Versions of Quizzes and Tests
11/27/2015          Your School Library II
08/28/2016          The First Days of School
01/12/2018          Grading Rubrics for Lab Reports
08/17/2018          Chemistry Using Virtual Reality

For the 2018/2019 school year, buy a copy of the lab book Chemistry on a Budget – it is a great resource! You can examine the labs and decide what you want to use during the school year.

*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.

Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.

Have a great weekend!

0 Comments

MOLE redefinition

gas explosion in boston

High-tech electronics made from autumn leaves

Airplane air concerns

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