What happens when platinum wire is heated?
When platinum wire is heated, no new substance is formed. The wire becomes white hard but is still platinum.
Is heating a platinum wire in air a physical change?
Heating a platinum wire, the final product is again platinum wire (as platinum is a noble metal and does not react with air), i.e. no change in composition and is a physical change. Heating magnesium wire forms MgO i.e. composition changes a new substance white powder of magnesium oxide is formed is a chemical change.
Why platinum wire is used for sealing in glass?
The extent of linear expansion is denoted using the coefficient of linear expansion. Coefficient of linear expansion is the rate at which a material of unit length expands when temperature is changed by one degree. Platinum and glass have the same coefficient of linear expansion. Hence, it can be sealed with glass.
Is platinum used to make electric wires?
Explanation: Copper and Aluminum are good conductors of electricity as they offer low resistance, hence they are used in electric wires. Gold, Platinum and Silver is used to make jewelry as they are less reactive. Graphite is the only non-metal that is a good conductor of electricity. So, it is used as electrodes.
Can platinum be heated?
Of the six metals of the platinum group, platinum alone remains untarnished on heat- ing in air at all temperatures under ordinary conditions, although Wohler (3) claimed to have produced temper colours on platinum foil by heating it for 16 days at 420-450°C.
What is platinum wire?
Platinum makes an especially valuable wiring material because of its consistent performance in high temperatures, complex configurations, and challenging environments. It resists corrosion and oxidation and withstands the majority of acids.
Why is heating a platinum wire reversible change?
Platinum is an noble metal which can be reversed at any state of matter as presence of impure state is nil, hence heating of platinum excites the electron and on cooling reverse to the normal state by loss of absorbed energy. The main reason for irreversible state is of its (Pt) non-reactivity to Oxygen in air.
What metallic wire is fused in glass?
Due to its low thermal expansion coefficient, matched to glass, tungsten is frequently used for glass-metal bonds. Tungsten forms satisfying bonds with glasses with similar thermal expansion coefficient such as high-borosilicate glass.
Why in drinking hot water a thin bottomed glass is taken?
If the glass is thick, the outer layer will still be cold as hot water makes contact with the inner layer creating an important thermal stress. If the glass is thin, it will heat up faster and more homogeneously, resulting in lower thermal stress and rupture be less likely to occur.
What is platinum used for?
Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry.
Why is platinum used in circuits?
Adding platinum to the cobalt magnetic alloy enhances the magnetic properties of the surface and therefore its storage capacity. Platinum, palladium, rhodium and iridium are used to coat electrodes, the tiny components in all electronic products which help to control the flow of electricity.
Is platinum a hard metal?
Platinum is not a hard metal. It is 4 – 4.5 on the MOHs scale of hardness. This means it can be scratched by anything harder than it is. That’s about the same hardness as your fingernail.