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Questions in chemistry

[Terjawab] A student investigated the rate of reaction between sodium thiosulphate and dilute hydrochloric acid. - The student placed a conical flask over a cross on a piece of paper. - The student mixed the solutions in the flask. - The solution went cloudy. - The student timed how long it took until the cross could not be seen. The equation for the reaction is: \[ \text{Na}_2\text{S}_2\text{O}_3(aq) + 2\text{HCl}(aq) \rightarrow 2\text{NaCl}(aq) + \text{H}_2\text{O}(l) + \text{SO}_2(g) + \text{S}(s) \] Explain why the solution goes cloudy.

[Terjawab] Thermosoftening polymers can be used to make plastic bottles and food packaging. 1) The reaction to produce polymers uses a catalyst. Why does the catalyst work for a long time before it needs replacing? 2) Thermosoftening polymers would not be suitable for packaging very hot food. Explain why in terms of their properties and structure.

[Terjawab] Is glass biotic or abiotic?

[Terjawab] The reaction described in Part A required 3.98 L of calcium chloride. What is the concentration of this calcium chloride solution?

[Terjawab] What is the sum of 0.04321 g + 5.263 g + 2.13 g to the correct number of significant digits?

[Terjawab] What element is a white, shiny, metallic solid that reacts slightly to air and has a density of 1.55?

[Terjawab] Methane, CH4, can be used as fuel in an automobile to reduce pollution. What is the coefficient of oxygen in the balanced equation for the reaction? __CH4(g) + __O2(g) → __CO2(g) + __H2O(g)

[Terjawab] Given that P-31 is the only natural isotope of phosphorus, what is the mass of one phosphorus atom and the mass of Avogadro's number of phosphorus atoms, respectively?

[Terjawab] List three ways you can use an electric current. Describe the energy change that takes place.

[Terjawab] What element has atoms that can form halide ions?