A test tube becomes cool to the touch.
Explanation:
The signs for an endothermic reaction would most likely be that a test tube becomes cool to touch. An endothermic reaction is a reaction in which heat is absorbed from the environment.
- At the end of this heat change, the surrounding becomes colder.
- Most endothermic reactions are always shown by the test tube becoming colder.
- For exothermic reaction in which heat is given off to the surroundings, the tube should be hotter.
Learn more:
Exothermic reactions brainly.com/question/10567109
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The energy of the light with a wavelength of 415 nm is not sufficient to remove an electron from a silver atom in the gaseous phase.
<h3>Energy and wavelength of light</h3>
The energy and wavelength of light are related by the formula given below:
- Energy = hc/λ
- where, E = energy
- h = Planck's constant
- c = velocity of light
- λ = wavelength of light
<h3>Calculating the energy of the light</h3>
From the data provided:
- h = 6.63 × 10^-34 Js
- c = 3.0 × 10^8 m/s
- λ = 415 nm = 4.15 × 10^-7 m
E = (6.63 × 10^-34 × 3.0 × 10^8 m/s)/4.15 × 10^-7 m
E = 4.79 × 10^-19 J
Energy of light is 4.79 × 10^-19 J
Compared with the ionization energy of silver, the energy of the light is far less.
Therefore, the energy of the light with a wavelength of 415 nm is not sufficient to remove an electron from a silver atom in the gaseous phase.
Learn more about about ionization energy and energy of light at: brainly.com/question/14596067
Answer:
C. 2.70 g/mL
Explanation:
Density is the ratio between the mass of a substance and the volume it occupies. Based on Archimedes' volume, the displaced volume of the aluminium is the volume it occupies. To solve this question we must find the difference in volume between initial volume of water = 30mL and final volume of water + aluminium = 39.26mL. This difference is the volume of the aluminium. With its mass we can find density:
39.26mL - 30mL = 9.26mL
Density = 25.00g / 9.26mL =
2.70g/mL
Right answer is:
<h3>C. 2.70 g/mL
</h3>
The answer is: 197 grams
Why?
All 20 grams of aluminum was used to form aluminum bromide. Only 177 grams of bromide were used to make aluminum bromide, since 23 grams were left over.
20 grams + 177 grams = 197 grams, so the answer is 197 grams.
The oxidation number of chlorine in the reactant can be determined by K ion and O ion. K ion is +1 and O ion is -2. And the Cl is +5. The gas has the greatest entropy and the solid has the least. In the production, there are solid and gas. So it has more entropy than the reactants with solid only.
