# Tag Info

24

Measure the change in mass over time of the remaining liquid. Though some water will also evaporate, you can control for that by keeping the humidity near 100%. If you have to be precise, collect the outgassed $\ce{CO2}$ in a liquid-nitrogen cold trap. Check the mass of the condensate, which should equal that lost from the soda. Check purity, to be really ...

12

Measure concentration in a fixed volume of air Easiest way might be to put it in a sealed impermeable bag or box and measure the CO2 concentration over time. Home hobbyists use something like the MG-811 CO2 sensor or a simple non-dispersive optical sensor and connect it to a Raspberry Pi or Arduino using an analog to digital converter chip (ADC). For (a ...

9

In the absence of other chemicals you can utilize the fact that nitrates(V) are much stronger oxidizing agents than phosphates(V). You can soak a piece of newspaper in a saturated solution of the salt, let it dry well in a ventilated place and try to ignite it. If the salt was $\ce{KNO3}$, it will burn vigorously and fast (that's why kids are often using ...

8

Well, given that one is a weak acid and the other is the salt of a strong base and a strong acid, the pH of a solution of the powder should tell you which it is. If it's $\ce{KNO3}$ it should neutral, and if it's $\ce{KH2PO4}$ it should be acidic. Just need some pH paper, which you could probably buy at a pool supply store.

6

For a direct measurement of $\ce{CO2}$ content, it is possible to use infrared (IR) spectroscopy. Infrared radiation can be absorbed by molecules, causing them to vibrate. The exact frequency of the radiation absorbed is often characteristic of certain bonds or functional groups. In particular, the fundamental antisymmetric stretching mode of $\ce{CO2}$ in ...

5

You don't have to reinvent the wheel. Food industry already uses quite simple oxygen scavengers for decades, and one of the most affordable formulations include iron powder mixed with sodium chloride. Typically, an oxygen scavenger is packaged in small packets (sometimes labeled as "oxygen absorber" or "antioxidant") that are added with the product inside ...

5

Yes, this really happened, probably (it's not a peer-reviewed effort). The reactor is a Farnsworth fusor, a very low-density, low-rate inertial-confinement reactor. They're surprisingly easy to build and get working; many people have done so, and verified their function by measuring neutron output. An accelerating voltage of 10 or 20 kV produces particle ...

5

From the Institute of Minerals, Materials and Mining, Most aluminium foil is made from pure aluminium, but increasingly alloys are used to improve properties and reduce the thickness required. If you want to make sure that the Aluminium foil you're using is pure, the only way would probably to ask the manufacturer. Other than that, it could be the case ...

4

The voltage you measure between the terminals of a voltaic cell will depend on two factors: The intrinsic maximum voltage $(V_\mathrm{max} = E_\mathrm{cell})$ that the cell could produce, depending on the $E^o_{red}$ of each half cell, the ion concentrations and the temperature. This is calculated from the Nernst equation: E_\mathrm{cell} = E^⦵_\mathrm{...

4

Water contains negligible amount of $\ce{CaCO3}$ or $\ce{MgCO3}$, as these are almost insoluble in water. What you are interested in are bicarbonates $\ce{Ca(HCO3)2 + Mg(HCO3)2}$. Their content is known as the temporary or carbonate water hardness that can be expressed as $\ce{CaCO3}$ equivalent. The complement to the carbonate hardness is the permanent ...

4

Touch medium samples of both salts with a glowing ember. No noticable effect would be observed on contact with $\ce{KH2PO4}$. Contact with $\ce{KNO3}$ shall produce noticeable flame. Video https://www.youtube.com/watch?v=dJRqJ145dyM

4

Well, it would actually make things a little awkward. Why do Vinegar and baking soda work? The reason for the usage of vinegar or sodium bicarbonate must first be understood. Vinegar ($\ce{CH3COOH}$) is an acid, and hence protonates the carbonyl oxygen present in urea[1]. $\ce{NaHCO3}$ (baking soda) is amphoteric, meaning it can react with both acids and ...

4

After the edits by the original post, the OP clarified that they used a hypochlorite (not an oxygen bleach as stated earlier) and left a piece of steel wool in it. Due to corrosive nature of chloride/hypochlorite, the steel wool crumbled to iron (III) oxides. When you gently heat rust in highly alkaline medium in the presence of hypochlorite ion, it forms a ...

4

You might want to use a $\ce{CO2}$ ion selective electrode, such as PS-3517 from PASCO: This Carbon Dioxide Ion Selective Electrode (ISE) Probe is a gas-sensing electrode that allows fast, simple, eco-nomical, and accurate measurement of dissolved CO2 in aqueous solutions The advantage over other methods is that you measure the concentration in situ and ...

3

Things are more complex than you suppose There are two key reasons why these compounds burn with different smells. The first is that your assumption about what the substances contain is wrong. Biological fibres contain plenty other than carbon and hydrogen. Often they will have lots of nitrogen and sulphur and various other elements and these often produce ...

3

Aluminum oxide does not react with sulphates, even at high temperature. Anyway, aluminum sulphate does not support high temperatures : it is easily decomposed at around 700°C.

3

I agree. This is a dangerous reaction and should not be tried without proper equipment, including a lab hood and fire extinguishing equipment. The fumes could be "just" droplets of sodium hydroxide solution. I've seen similar fumes involving hydrochloric acid, just by adding water to rinse out traces of concentrated acid (in a hood, of course). They may ...

3

I am assuming by chalk you meant you were using blackboard chalk. In which case Ivan's comment was close, but all the other comments have completely missed the issue. The reason you saw no reaction is because chalkboard chalk isn't actually chalk, it is typically gypsum which is chemically calcium sulfate ($\ce{CaSO4}$) which is inert to acid. Chalk the ...

3

On 2019-11-29 Ben Krasnow uploaded a YouTube video DIY mass spectrometer measures potassium in dietary salt substitute showing an outstanding construction of a mass-spec apparatus in his home shop based on the articles by Dewdney [1] and Stong [2] with some variations and improvements, like altered electrical scheme and increased emission current. The main ...

3

A very different method which should work well given the high initial level of carbonation in Coca-Cola (141 mM by my estimation based on this post) is $\ce{^{13}C}$-NMR. See for instance Reference 1. Spectra of liquid solutions are high in resolution and one dimensional data can be acquired continuously in a span of a few minutes per spectrum. Note ...

2

If the solution is not too concentrated and you dont need it to be stable for a prolonged period, many viscosity modifiers can be used. I would start trying something simple, like CMC based wallpaper paste.

2

TL;DR: Use 10-20% urea solution for octahedral crystals and a water-ethanol mix for pyramidal crystals. There is no universal method to predict and to control crystal habits. Very often the experimental results are explained with molecular dynamics; there are models (Wulff condition, Donnay–Harker correlation, Hartman–Perdok theory, Hartman–Bennema ...

2

I think this is a chemistry question, so I will answer it here. First, I would question whether the amount of $\ce{CO2}$ is relevant or the concentration (or if more convenient, partial pressure). There is no way for the bed bugs to integrate over the entire trap vs. the bed. If you have a concentration gradient from bed to trap, it should work. Second, ...

2

There is not many simple tests. One of possible tests would be passing gas through neutral solution of suitable acidobasic colour indicator, e.g bromthymol blue, turning green to yellow while getting slightly acidic. But it would not be specific, any acidic gas would do that. You have not mentioned context, why do you need to know ? Or is it just homework-...

2

Your small copper-zinc cell may not light up a bulb as often shown in textbooks. Check your ammeter settings, it must show some current. How are you connecting it in series? voltmeter is connected in parallel. Now an interesting question. Imagine you join 12 (e.g., Duracells) in series to generate about 12 Volts. Can one start a car with 12 Duracells? Why do ...

2

You could heat it to turn bicarbonate into carbonate, and let it stand with Ca(OH2) and water mix. That's essentialy how potash lye was made for millenia

2

Potassium permanganate solution tends to decompose with time, especially those which are not acidified. Just let an aqueous solution sit in a glass bottle and it will leave a brown film of tenacious manganese dioxide on the surface at room temperature. If water has any organic material, it will become brown and tap water is not pure water. It decomposes on ...

2

Concrete is frequently treated with dilute hydrochloric acid to etch the surface prior to painting or coating with epoxy. After treatment with acid, good rinsing is suggested. This etch treatment will react with CaCO3 at the surface (Ca(OH)2 produced as a product of the hydration of cement reacts with CO2 in the air to form CaCO3 over a period of months), ...

2

Reynolds Kitchens says Relnolds Wrap® is $98.5\%$ $\ce{Al}$ with the rest mostly $\ce{Fe}$ and $\ce{Si}$ to improve strength. You know this because when you dissolve it in $\ce{NaOH}$ solution to produce $\ce{H_2}$ a black residue remains undissolved; pure $\ce{Al}$ metal would leave no residue. Perhaps $\ce{Al}$ wiring would be more nearly pure because ...

1

Fire requires three things: heat, fuel and oxygen. When burning a cotton ball, a match will provide heat, the cellulose fibers will provide fuel and the air will provide oxygen. It is the amount of oxygen in the air that causes the cotton to burn relatively slowly. By soaking the cotton in Sulfuric Acid and Nitric Acid, the hydrogens that were attached to ...

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