Answer:
45 g of the solid Tris will be dissolved in 2.5 liters of water.
Explanation:
Recall that:
<em>Number of moles = molarity x volume</em>
Hence, number of moles of Tris present in 2.5 liters, 150 mM solution:
= 150/1000 x 2.5 = 0.375 moles
Also, recall that:
<em>No of moles of substance = mass/molar mass.</em>
Hence, mass of 0.375 moles substance:
= no of moles of the substance x molar mass of the substance.
= 0.375 x 120 = 45 g.
Therefore, in order to prepare 2.5 liters, 150 mM of an aqueous solution of Tris, 45 g of the solid Tris will be dissolved in 2.5 liters of water.
Answer:
Air pollution harms human health and the environment. In Europe, emissions of many air pollutants have decreased substantially over the past decades, resulting in improved air quality across the region. However, air pollutant concentrations are still too high, and air quality problems persist. A significant proportion of Europe’s population live in areas, especially cities, where exceedances of air quality standards occur: ozone, nitrogen dioxide and particulate matter (PM) pollution pose serious health risks. Several countries have exceeded one or more of their 2010 emission limits for four important air pollutants. Reducing air pollution therefore remains important.
Air pollution is a local, pan-European and hemispheric issue. Air pollutants released in one country may be transported in the atmosphere, contributing to or resulting in poor air quality elsewhere.
Particulate matter, nitrogen dioxide and ground-level ozone, are now generally recognised as the three pollutants that most significantly affect human health. Long-term and peak exposures to these pollutants range in severity of impact, from impairing the respiratory system to premature death. Around 90 % of city dwellers in Europe are exposed to pollutants at concentrations higher than the air quality levels deemed harmful to health. For example, fine particulate matter (PM2.5) in air has been estimated to reduce life expectancy in the EU by more than eight months. Benzo(a)pyrene is a carcinogenic pollutant of increasing concern, with concentrations being above the threshold set to protect human health in several urban areas, especially in central and eastern Europe.
"Air pollution is causing damage to human health and ecosystems. Large parts of the population do not live in a healthy environment, according to current standards. To get on to a sustainable path, Europe will have to be ambitious and go beyond current legislation."
Explanation:
Answer:
The answer is C - Theories are supported with evidence and do explain what we see in the world (Ex: The cell theory) The evidence can change or be added on to when new evidence is found.
Explanation:
A - Theories are not hypotheses but theories start out as hypotheses. When the hypotheses gain enough evidence, they can start to become a theory, and this is after many experimentations and testings and trials and research.
B - Everyone can have theories, not just scientists. Many theories have been made on social media platforms such as r e d d i t or y o u t u b e. Some of these theories are conspiracy theories that people make based on some evidence they gather about a topic and sometimes believe is true even though it may not be true.
D - Theories are not opinions but are backed up with evidence and may have went through many trials and errors to become where it is.
E - Theories are testable ideas and scientists are always trying to make theories to be the best of what it can be. Theories have to be tested over and over again to make sure that whatever the theory is about is still valid and works.
Explanation:
sorry for the handwriting
DNA helicase is the enzyme that opens the double helix
