Some salts make hydrates when there is moisture around. Some hydrate samples can absorb lights in visible legion. Therefore, they show some colors. Thus, hydrates can be used to detect the moisture in the environment. Let's say you are working in a laboratory with a group and you are the only student who has taken chemistry courses. Your laboratory received a sample of cobaltçii) chloride which has the formula Cocl2-XH20. Let's say your boss asked you to find the formula of this hydrate salt sample since you are the only chemist there. From your laboratory experience, simply explain the experimental procedure you would follow to find the formula of this unknown sample. Then, use the given data for the calculation part. Mass of crucible: 32.27g Mass of crucible + unknown hydrate: 33.92 g Color of unknown hydrate: purple Mass of crucible + anhydrous form of hydrate: 33.41 g Color of anhydrous form: sky blue

Modern commercial airliners are largely made of aluminum, a light and strong metal. But the fact that aluminum is cheap enough that airplanes can be made out of it is a bit of historical luck. Before the discovery of the Hall-Héroult process in 1886, aluminum was as rare and expensive as gold. What would happen if airplanes had to be made of steel? The fuselage of the Boeing 777, which can carry 305 passengers, is approximately a hollow aluminum cylinder without ends, 64.0 m long, 6.2 m wide, and 2.5 mm thick (see sketch at right). The fuselage of an airplane Suppose this fuselage was made of steel (density 7.87 g/cm³) instead of aluminum (density 2.70 g/cm³), and let's say the average passenger has a mass of 81 kg. We'll also assume the engines can't lift any greater mass than they already do. Calculate the number of passengers that the Boeing 777 could carry if its fuselage was made of steel. X Ś

1. More than 2000 years ago human cultures figured out a way to produce iron metal from rocks containing iron ores. This iron could be worked by a blacksmith (repeated heating and hammering) to make iron metal pure enough for creating useful tools (even Samurai swords). This direct heating technique was common up until about 200 years ago when people found a better way to obtain iron metal. When hematite, Fe2O3(s), is strongly heated in a blast furnace in the presence of charcoal (carbon), pure iron metal is obtained. Fe2O3() 2 Fe(s) + 3/2 O2 (g) (1) C(s) + O2 (g) → CO2(g) (2) When reaction 1 is coupled to reaction 2, overall chemical equation is Fe2O3() + 3/2 C() 3/2 CO2(g) + 2 Fee) Use the thermodynamic data given below for the following calculations: AG¡ (kJ/mol) | 4H¡ (kJ/mol) | S (J/mol-K) Fe2O3(s) -742.2 -824.2 87.40 Fes) 27.28 CO2(8) -394.36 -393.51 213.74 C (6) 5.74 O2 (2) 205.14 a) Calculate the standard Gibb's free energy change for reaction 1 b) Calculate the standard Gibb’s…

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Which of the following statements regarding atomic Br and Cl is FALSE? O Atomic Br is more efficient at catalytically destroying ozone than atomic Cl in the stratosphere due to a relatively higher proportion of the Br atoms being in a catalytically active form at any given time.

Which of the following compounds would most likely have the highest melting point? NaCl NaF CaCl2 Li₂O

Give the noble gas shorthand notation (ex: [He] 2s2 2p1) for Br       Give the noble gas shorthand notation (ex: [He] 2s2 2p1) for Ca+2       Give the noble gas shorthand notation (ex: [He] 2s2 2p1) for Zn

How many grams of the 90% pure gold must a smith use with a 65% pure gold alloy to make 5000 grams of an alloy which will be 70% gold?

What are the chemical equations of the following:  CuSO4 + HCl CoCl2 +HCl Ni(NO3)2 +HCl