The boiling point of a substance is the temperature that separates a liquid and a gas. What accounts for this variability?
I know from feedback that my gcse science summary revision pages have proved useful but they do not guarantee a high grade, that all depends on you and the factors mentioned in point 4. Please note that my GCSE science revision pages are designed to be used for online convenience, so, beware, printouts could be quite long!
Some quizzes, particularly the compilations, are quite large and take some time to download. Links to specific GCSE chemistry notes and quizzes about the topic in question have been added, and from these pages, you may find other links to more useful material linked to the topic.
In terms of old grades the following is an approximate comparison: Whilst the reactivity of chemicals is a significant factor in how fast chemical reactions proceed, there are many variables that can be manipulated in order to speed them up or slow them down.
Chemical reactions may also be reversible and therefore the effect of different variables needs to be established in order to identify how to maximise the yield of desired product. Understanding energy changes that accompany chemical reactions is important for this process.
In industry, chemists and chemical engineers determine the effect of different variables on reaction rate and yield of product.
Whilst there may be compromises to be made, they carry out optimisation processes to ensure that enough product is produced within a sufficient time, and in an energy efficient way. Factors affecting the rate of a chemical reaction - temperature, concentration, particle size, catalysts etc.
You should be able to: In the context of rates of reaction data, you must be able to Recognise and use expressions in decimal form. Use ratios, fractions and percentages.
Make estimates of the results of simple calculations. Translate information between graphical and numeric form. Plot two variables from experimental or other data. Determine the slope and intercept of a linear graph.
Draw and use the slope of a tangent to a curve as a measure of rate of change.The Energy Division oversees oil and gas activities offshore Santa Barbara County and the onshore facilities that support those offshore operations and oil refineries, as well as renewable energy projects, including planning, policy development, permit processing, environmental review and risk analyses, permit enforcement and public outreach.
Note that La Nina cooling in the tropics has finally penetrated the troposphere, with a deg. C departure from average. The last time the tropics were cooler than this was June, ( deg. C). Out of the month satellite record, the deg.
C one-month drop in January tropical.
* Two common measures of energy are British thermal units (Btu) and joules. All forms of energy can be expressed in these units. One Btu is the amount of energy needed to raise the temperature of one pound of water from 39 to 40 degrees Fahrenheit.
One joule is the amount of energy needed to lift one hundred grams ( ounces) upward by one meter ( feet) while on the surface of the earth. Units and significant figures Candidates should be aware that misuse of units and/or significant figures, i.e.
failure to quote units where necessary, the inclusion of units in quantities defined as ratios or quoting answers to an inappropriate number of significant figures, is liable to be penalised.
Heroes and Villains - A little light reading. Here you will find a brief history of technology. Initially inspired by the development of batteries, it covers technology in general and includes some interesting little known, or long forgotten, facts as well as a few myths about the development of technology, the science behind it, the context in which it occurred and the deeds of the many.
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