Chemical Functions, Indicators, pH and Modern Theories Here are our solved exercises on this content. To see the answers, just click the button next to each question. 1. What are acid-base indicators? 2. What are the best known acid-base indicators? 3. What color does phenolphthalein assume when it comes in contact with an acid?
1. A rectilinear conductor is traversed by an electric current of intensity i = 2,0A when immersed in a uniform magnetic field of intensity B = 0,0002T, which is the magnetic force in a section of this conductor of length l = 20cm, In the following cases: (a) For cases where the angle formed between the magnetic field and the current is 0, the force exerted by the field is 0, for: But sin0 ° = 0, therefore F = 0.
It is the phenomenon that occurs when a wave passes from one medium to another of different characteristics, having its direction deviated. Regardless of each wave, its frequency does not change in refraction, however, the speed and wavelength may change. Through refraction it is possible to explain numerous effects such as the rainbow, the color of the sky at sunset and the construction of astronomical devices.
In countries where the weather is very cold, it is common to add special additives to car radiators to prevent water freezing. Using one of the knowledge of colligative properties, cryoscopy, it is customary to add ethylene glycol to the radiator water. This causes the freezing temperature to decrease and causes the boiling temperature to increase.
Blackbody is an ideal body that absorbs all incident thermal radiation. It is therefore a perfect absorber, since its absorption power is 1. Even though it is an idealization, there are several ways to obtain bodies with black-body behaviors. For example, we can coat any body with an irregular layer of black pigments.
Catalytic Hydrogenation This addition reaction occurs in alkenes and alkynes. Hydrogen gas is added with the help of a catalyst. Nickel (Ni) or platinum (Pt) metal can be used. We may also call this reaction reaction Sabatier-Senderens. It is well known in the food chemical industry, serving as the basis for the production of margarines from vegetable oils.