A freshly isolated sample of 90y was found to have an activity of 5.0 × 105 disintegrations per minute at 1:00 p.m. on december 3, 2006. at 2:15 p.m. on december 17, 2006, its activity was measured again and found to be 1.3 × 104 disintegrations per minute. calculate the half-life of 90y.
A radioactive isotope of copper decays as follows: 64cu → 64zn + 0 β −1 t1/2 = 12.8 h starting with 92.0 g of 64cu, calculate the quantity of 64zn produced after 14.3 h.
Consider the molecule h2co. using valence bond theory, describe the location of the carbon electrons as it prepares to form bonds with the other atoms.
By the end of this lab, you will determine whether you should add cocoa mix (a solid) before or after heating water (liquid) to make hot chocolate. State a broad question about solubility whose answer would help you determine this.
Desalinization plants remove the salt from sea water and make it usable for drinking and irrigation. Review the following statements and select the one that best describes how this technology has had a positive impact on the environment. A.Desalinization plants are expensive to build and maintain; however, on some small islands, where there is no […]
A sample of CO2 gas with 10.0 L of volume and 60.0 torr of pressure is mixed with a sample of O2 gas with 20.0 L of volume and 50.0 torr of pressure, in a large container with 30.0 L of volume. What is the final volume of O2?
A 30.0 L container was filled by pumping into it 10.0 L of CO2 gas at 60.0 torr of pressure and 20.0 L of O2 gas at 50.0 torr of pressure. All volumes and pressures were measured at the same temperature. What is the final pressure of CO2 in this mixture?
A chemist takes 50-gram sample of sulfur powder that has a melting point of 115.2 °C. What is the melting point of a 100-gram sample of sulfur powder?
In which of the following pairs of salts will both members of the pair hydrolyze in water to give solutions that are basic? A. NaC2H3O2 and NaF B. LiCl and NaCN C. NH4Cl and NH4NO3 D. KNO3 and Li2SO4
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