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PbO was one of the raw materials for century eggs, a type of Chinese preserved egg. but it has been gradually replaced due to health problems. It was an unscrupulous practice in some small factories but it became rampant in China and forced many honest manufacturers to label their boxes "lead-free" after the scandal went mainstream in 2013.
Lead sesquioxide, Pb 2 O 3, which is a lead (II,IV) oxide as well (lead(II) metaplumbate(IV) [Pb 2+][PbO 2− 3]), reddish yellow Pb 12 O 19 , monoclinic, dark-brown or black crystals The so-called black lead oxide , which is a mixture of PbO and fine-powdered Pb metal and used in the production of lead–acid batteries .
PbO 2 + 2 NaOH + 2 H 2 O → Na 2 [Pb(OH) 6] It also reacts with basic oxides in the melt, yielding orthoplumbates M 4 [PbO 4]. Because of the instability of its Pb 4+ cation, lead dioxide reacts with hot acids, converting to the more stable Pb 2+ state and liberating oxygen: [6] 2 PbO 2 + 2 H 2 SO 4 → 2 PbSO 4 + 2 H 2 O + O 2 2 PbO 2 + 4 HNO ...
Lead(II,IV) oxide is lead(II) orthoplumbate(IV) [Pb 2+] 2 [PbO 4− 4]. [3] It has a tetragonal crystal structure at room temperature, which then transforms to an orthorhombic (Pearson symbol oP28, Space group Pbam, No. 55) form at temperature 170 K (−103 °C). This phase transition only changes the symmetry of the crystal and slightly ...
A new approach to a routine blood test could predict a person’s 30-year risk of heart disease, research published Saturday in the New England Journal of Medicine found.. Doctors have long ...
With a maximal stress test the level of exercise is increased until the person's heart rate will not increase any higher, despite increased exercise. A fairly accurate estimate of the target heart rate, based on extensive clinical research, can be estimated by the formula 220 beats per minute minus patient's age.
While the specific test is not automatically included in most cholesterol screenings, your doctor can order a separate blood test for it. Just don’t be surprised if the test—which can cost ...
Once the sample is obtained, [7] care is taken to eliminate visible gas bubbles, as these bubbles can dissolve into the sample and cause inaccurate results. The sealed syringe is taken to a blood gas analyzer. [8] If a plastic blood gas syringe is used, the sample should be transported and kept at room temperature and analyzed within 30 min.