The development of a 20-item semantic differential assessment instrument for measuring student attitudes toward the subject of chemistry is described (Attitude toward the Subject of Chemistry Inventory—ASCI). Instrument subscales and survey items pertain to interest and utility, anxiety, intellectual accessibility, emotional satisfaction, and fear. Detailed information on validity is provided by means of exploratory factor analysis, comparisons between different populations of students (general chemistry, peer leaders, chemistry majors), and comparisons with course performance. Reliability is established by estimation of internal consistency of subscales and retesting correlation. The instrument is useful for assessing student attitude for any curriculum setting for longitudinal change or intercomparison of groups. Specific application in an inquiry-based, nonmajors chemistry course is described.
A and B are constants related to the nature of the transfer ion and interface.(5) The linear relationship between the peak current and the concentration of BCG in the two phases can be used for BCG analysis, providing a new way for organic dye analysis.LITERATURE CITED
Our goal was to understand how students’
chemistry learning
environments changed and how students responded to the wholesale transition
to online learning. We deployed surveys to students enrolled in nine
undergraduate chemistry courses at all levels. Survey 1 was deployed
2 weeks post-transition (N = 208); Survey 2, a week
before semester’s end (N = 124, 1/3 new responders).
Survey 1 asked students to describe pre/post-transition class and
laboratory; to report extra-class resource use; and to write about
their engagement, emotions, and motivation for learning online. Survey
2 asked students to estimate pre/post-transition verbal exchanges
on a typical day; to respond to Likert-style questions constructed
from Survey 1 comments; and to describe challenges of learning chemistry
online including what they missed about laboratory. Results show classes
changed little from a traditional lecture while laboratories changed
dramatically from decision-rich first-person experiences to suboptimal
passive observation. Students were sorted into profiles, according
to described challenges and their adaptive behaviors. Written comments
and verbal exchange data show students lost rich peer communication
networks which was deleterious to understanding and motivation to
engage and persist. Unexpectedly, this study pointed out more clearly
the importance of cognitive processing limitations, social dynamics,
peer interaction, real-time discourse, and hands-on manipulation in
any educational setting (in-person or online).
Supported gold nanoparticles have generated an immense interest in the field of catalysis due to their extremely high reactivity and selectivity. Recently, alloy nanoparticles of gold have received a lot of attention due to their enhanced catalytic properties. Here we report the synthesis of silica supported AuCu nanoparticles through the conversion of supported Au nanoparticles in a solution of Cu(C(2)H(3)O(2))(2) at 300 °C. The AuCu alloy structure was confirmed through powder XRD (which indicated a weakly ordered alloy phase), XANES, and EXAFS. It was also shown that heating the AuCu/SiO(2) in an O(2) atmosphere segregated the catalyst into a Au-CuO(x) heterostructure between 150 °C to 240 °C. Heating the catalyst in H(2) at 300 °C reduced the CuO(x) back to Cu(0) to reform the AuCu alloy phase. It was found that the AuCu/SiO(2) catalysts were inactive for CO oxidation. However, various pretreatment conditions were required to form a highly active and stable Au-CuO(x)/SiO(2) catalyst to achieve 100% CO conversion below room-temperature. This is explained by the in situ FTIR result, which shows that CO molecules can be chemisorbed and activated only on the Au-CuO(x)/SiO(2) catalyst but not on the AuCu/SiO(2) catalyst.
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