# Questions tagged [units]

For questions about the definition and usage of units of measurement.

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### Units of rate constant (cycles per second vs radians per second) in Eyring equation

In the Eyring equation (EE), $$k = \frac{k_\mathrm B T}{h} \exp\left(\frac{-\Delta G_{\mathrm f}}{RT}\right),$$ the units of $k$ are $\mathrm{s^{-1}}$. However, in general rate constants are usually ...
0answers
488 views

### Calculating volume ethanol in an fermented aqueous solution of sucrose, water, and ethanol

I've been working on a biology experiment where I calculate the fermentation yield of yeast under various light induced stress responses inhibiting the translation of various fermentation enzymes. My ...
1answer
102 views

### Pressure change of a gas upon increasing the temperature

My assignment is as follows: A sample of air is trapped in a container at 16.2 psi. If the initial temperature is increased from 10°C to 32°C, what is the final pressure? I am really confused as ...
1answer
749 views

### Reaction rate constant conversion [closed]

I'm flustered, I'm not into chemistry and need to convert $\mathrm{(nM\cdot s)^{-1}}$ to $\mathrm{(M\cdot s)^{-1}}$. Is it correct to multiply with $10^9$?
1answer
5k views

### How dangerous is a megacurie (MCi)?

I was researching the Kyshtym (nuclear) Disaster, and it said that it released 20 MCi (20 megacuries) of radiation into the air in a dust cloud. I read from this Yahoo Answers answer that: The ...
1answer
14k views

### Convert from Pa to Pa to J/dm^3 [closed]

Given the value 380 PaK^-1, how do I convert Pa to Jdm-3? I know that 1 joule = 1 Nm, and that 1 pascal = 1 N/m^2. But where does the dm^-3 (or L) come into this? I don't know where to start.
3answers
490 views

### What is the physical quantity/magnitude of pH?

I have a database to classify variables/parameters in water resources as follows: Variable: Precipitation (P); Quantity: Length; Units of measurement: mm (millimeters). Following the example, what ...
1answer
206 views

### Find the displacement of mercury in a vertical tube

So we have a 1m tube sealed at both ends. It is initially horizontally placed and the middle 0.1m contains mercury and the two ends contain air. Now the tube is turned vertical, we have to find the ...
1answer
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### Do ALL conversion factors have an infinite number of sigfigs?

Conversion factors have an infinite number of sigfigs, right? They should be exact values; but not all of them are, are they? I looked at http://www.webassign.net/question_assets/buelemphys1/...
1answer
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### How is the unit of measure “equivalent” abbreviated?

I usually use "eq" but I have been told to use "equiv." in order to avoid confusion with "equation". Is there a reference I can check?
3answers
967 views

### Is 44.5 mg/L a measurement of weight or volume?

I have a test result that I am trying to fully grasp. I need to determine how much of a contaminant I need to reach that amount in 4,800 gallons. Making the conversion to liters is no problem, nor is ...
1answer
1k views

1answer
746 views

### How to compute the residence time for given flow rate in standard cubic meters?

I'm given a flow rate of a gas mixture of $3\ \mathrm{Nm^3/h}$ in standard cubic meters through a cylinder of length $50\ \mathrm{cm}$ and cross section $70\ \mathrm{cm^2}$, can I compute how long a ...