scholarly journals Understanding Le Châtelier’s principle fundamentals: five key questions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Miguel Peris
Keyword(s):  
General Chemistry ◽  
Chemical Reaction ◽  
Chemical Equilibrium ◽  
Secondary Level ◽  
Challenging Problem ◽  
Full Understanding ◽  
Different Types ◽  
Key Questions

Abstract The well-known Le Châtelier’s principle is almost always mentioned when dealing with chemical equilibrium. Nevertheless, although a must in most general chemistry courses starting from the secondary level, when students face questions about it, some major misconceptions are often highlighted; to avoid this, a somewhat challenging problem is now presented. It can be deemed a very useful tool for a full understanding of this principle and chemical equilibrium as a whole. A generic chemical reaction at equilibrium is subject to different types of perturbation, and the student is required – in each case – to identify the new position of equilibrium among a number of proposals. The correct answers are finally provided along with the corresponding explanations.

5. The Consequences of Democracy and Authoritarian Regimes

2019 ◽  
pp. 70-96
Author(s):  
Andrea Kendall-Taylor ◽  
Natasha Lindstaedt ◽  
Erica Frantz
Keyword(s):  
Quality Of Life ◽  
Economic Performance ◽  
Authoritarian Regimes ◽  
Regime Type ◽  
Political Systems ◽  
Different Types ◽  
Key Questions

Key themes 72 Regime type and conflict 74 Regime type and terrorism 78 Regime type and economic performance 81 Regime type and quality of life 86 Regime type and corruption 89 Regime type and repression 92 Conclusion 94 Key Questions 94 Further Reading 95 So far we have focused on defining different types of political systems. We discussed how to distinguish democracy from autocracy and the rising prevalence of ...

scholarly journals On chemical dynamics and statics under the action of light

1902 ◽  
Vol 70 (459-466) ◽  
pp. 66-74
Keyword(s):  
Chemical Reaction ◽  
Chemical Equilibrium ◽  
Heterogeneous Systems ◽  
The Other ◽  
Chemical Dynamics ◽  
Homogeneous Systems ◽  
General Law ◽  
Statics And Dynamics ◽  
The Law ◽  
Simple Nature

Since the second half of the last century chemical statics and dynamics have developed into a veritable science of their own. The general law governing velocity of chemical reaction and chemical equilibrium in homogeneous systems is now known as the law of action of mass; the law governing velocity of physical or molecular transformations in heterogeneous systems proves also to be of a general and simple nature: the velocity is directly proportional to the surface of contact of the reacting parts and to the remoteness of the system from the point of equilibrium;! the velocity of chemical reaction in heterogeneous systems and chemical equilibrium in heterogeneous systems represent no phenomena sui generis , and the laws governing them are only combinations of the other two laws mentioned.

scholarly journals Synaptic Dynamics as Convolutional Units

2020 ◽  
Author(s):  
Julian Rossbroich ◽  
Daniel Trotter ◽  
Katalin Tóth ◽  
Richard Naud
Keyword(s):  
Neural Networks ◽  
Action Potentials ◽  
Computational Models ◽  
Mathematical Framework ◽  
Challenging Problem ◽  
Maximum Likelihood Approach ◽  
Different Types ◽  
Likelihood Approach ◽  
Synaptic Dynamics ◽  
Nonlinear Operation

AbstractSynaptic dynamics differ markedly across connections and strongly regulate how action potentials are being communicated. To model the range of synaptic dynamics observed in experiments, we develop a flexible mathematical framework based on a linear-nonlinear operation. This model can capture various experimentally observed features of synaptic dynamics and different types of heteroskedasticity. Despite its conceptual simplicity, we show it is more adaptable than previous models. Combined with a standard maximum likelihood approach, synaptic dynamics can be accurately and efficiently characterized using naturalistic stimulation patterns. These results make explicit that synaptic processing bears algorithmic similarities with information processing in convolutional neural networks.Author summaryUnderstanding how information is transmitted relies heavily on knowledge of the underlying regulatory synaptic dynamics. Existing computational models for capturing such dynamics are often either very complex or too restrictive. As a result, effectively capturing the different types of dynamics observed experimentally remains a challenging problem. Here, we propose a mathematically flexible linear-nonlinear model that is capable of efficiently characterizing synaptic dynamics. We demonstrate the ability of this model to capture different features of experimentally observed data.

scholarly journals Modeling the influence of external factors on students' memorization performance in general chemistry

2021 ◽  
Vol 101 ◽  
pp. 03035
Author(s):  
Vladimir Shelontsev ◽  
Irina Gerasimova
Keyword(s):  
General Chemistry ◽  
External Factors ◽  
Multivariate Methods ◽  
Empirical Justification ◽  
Methods Of Analysis ◽  
Different Types ◽  
Learning Chemistry

The article provides theoretical and empirical justification for the use of multivariate methods of analysis to implement different types of models in the study of the productivity of involuntary and combined memorization by students in learning chemistry.

scholarly journals TEST SAMPLES AND METHODS FOR THEİR SOLUTİON USED BY THE STATE EXAMİNATİON CENTER OF AZERBAİJAN REPUBLİC İN ASSESSİNG THE KNOWLEDGE OF ELEVENTH GRADE STUDENTS ON THE TOPİC "THE RATE OF CHEMİCAL REACTİON AND CHEMİCAL EQUİLİBRİUM"

2021 ◽  
pp. 12-17
Author(s):  
N. Matanat ◽  
A. Mutallim
Keyword(s):  
Chemical Reaction ◽  
Chemical Equilibrium ◽  
The State ◽  
Solution Methods ◽  
State Examination

In the article the test samples and their solution methods used by the State Examination Center of Azerbaijan Republic in the assessment of student's knowledge on the topic"The rate of chemical reaction and chemical equilibrium" are explained.

scholarly journals Behavior of mortars with different types of cement when induced to Delayed Ettringite Formation (DEF)

2021 ◽  
Vol 11 (3) ◽  
pp. 1-16
Author(s):  
Friancieli Tiecher ◽  
Marinês Langoski ◽  
Nicole Hasparyk
Keyword(s):  
Chemical Reaction ◽  
Curing Temperature ◽  
Delayed Ettringite Formation ◽  
Microstructural Characteristics ◽  
Evaluation Period ◽  
Ettringite Formation ◽  
Different Types ◽  
Early Strength ◽  
Over Time

The purpose of this paper is to present an evaluation of different types of cement and the incidence of Delayed Ettringite Formation (DEF) through mortar composites cast in the laboratory and exposed to a high curing temperature over a 12-month study period. DEF represents one of the types of Internal Sulfate Attacks (ISA) related to an expansive chemical reaction that occurs inside of concrete involving the sulfates from cement. Experiments involved the assessment of expansions, compressive and tensile strengths as well as microstructural characteristics over time. It was observed that tests performed on mortars and with a specific mix required an extended evaluation period to distinguish the behaviors. Furthermore, high early-strength cement featured the worst binder when faced with DEF.

Chemical Equilibrium

2021 ◽  
pp. 254-275
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Equilibrium Constant ◽  
Chemical Reaction ◽  
Chemical Equilibrium ◽  
Equilibrium Position ◽  
Dynamic Equilibrium ◽  
Reaction Conditions ◽  
The Relationship ◽  
Equilibrium Calculations

Chemical Equilibrium reviews the principles of equilibrium in systems of gases and liquids, starting with the concepts of reversible and irreversible reactions and dynamic equilibrium. The equilibrium constant (K) and reaction quotient (Q) are described, and comparison of K and Q is used to determine the direction in which a reaction must proceed to reach equilibrium. Calculations involving K in terms of concentration and pressure are presented. The relationship between the magnitude of K, the equilibrium position and the concentrations of reactants and products is discussed for both homogeneous and heterogeneous equilibria. The chapter ends with a qualitative treatment of equilibrium based on Le Chatelier’s principle, as well as how changes in reaction conditions can disturb a chemical equilibrium and how the chemical reaction responds to those changes.

scholarly journals Nodes Localization in 3D Wireless Sensor Networks Based on Multidimensional Scaling Algorithm

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Biljana Risteska Stojkoska
Keyword(s):  
Multidimensional Scaling ◽  
Heuristic Method ◽  
Three Dimensional ◽  
Wireless Sensor ◽  
Indoor Environments ◽  
Smart Environment ◽  
Challenging Problem ◽  
Computing Technology ◽  
Key Technology ◽  
Different Types

In the recent years, there has been a huge advancement in wireless sensor computing technology. Today, wireless sensor network (WSN) has become a key technology for different types of smart environment. Nodes localization in WSN has arisen as a very challenging problem in the research community. Most of the applications for WSN are not useful without a priory known nodes positions. Adding GPS receivers to each node is an expensive solution and inapplicable for indoor environments. In this paper, we implemented and evaluated an algorithm based on multidimensional scaling (MDS) technique for three-dimensional (3D) nodes localization in WSN using improved heuristic method for distance calculation. Using extensive simulations we investigated our approach regarding various network parameters. We compared the results from the simulations with other approaches for 3D-WSN localization and showed that our approach outperforms other techniques in terms of accuracy.

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