Science

A structural component in the form of a wide plate is to be fabricated from a steel alloy that has a plane strain fracture toughness of 98.9 MPa root m (90 ksi root in.) and a yield strength of 860 MPa (125,000 psi). The flaw size resolution limit of the flaw detection apparatus is 3.0 mm (0.12 in.). If the design stress is one-half of the yield strength and the value of Y is 1.0, determine whether or not a critical flaw for this plate is subject to detection.

EXPERT ANSWER

4. a) Draw an enthalpy diagram for a general endothermic reaction; label the axis, reactants, products, and DH with its sign. [2 marks] b) Given the following choices of reactants, write balanced total ionic and net ionic equations that best represent the reaction: [2 marks] (i) KNO3(aq) + CuCl(aq) – ? (ii) NaClO (aq) + CaCl(aq) – ? (iii) Li,SO (aq) + AgNO3(aq) – ? (iv) NH Br(aq) + Pb(CH3COO)2(aq) – ? c) When each of the following pairs of aqueous solutions is mixed, does a precipitation reaction occur? If so, write balanced molecular equations for: [1 Mark] (i) Potassium carbonate + Barium hydroxide (ii) Aluminum nitrate + Sodium phosphate TIL

EXPERT ANSWER a) Enthalpy diagrams are an easy way to see how the energy changes in a reaction over time. If delta H is positive then it’s an endothermic reaction and the product energy is higher than the starting energy. If delta H is negative then it’s an exothermic reaction and the product energy is lower than the starting …

4. a) Draw an enthalpy diagram for a general endothermic reaction; label the axis, reactants, products, and DH with its sign. [2 marks] b) Given the following choices of reactants, write balanced total ionic and net ionic equations that best represent the reaction: [2 marks] (i) KNO3(aq) + CuCl(aq) – ? (ii) NaClO (aq) + CaCl(aq) – ? (iii) Li,SO (aq) + AgNO3(aq) – ? (iv) NH Br(aq) + Pb(CH3COO)2(aq) – ? c) When each of the following pairs of aqueous solutions is mixed, does a precipitation reaction occur? If so, write balanced molecular equations for: [1 Mark] (i) Potassium carbonate + Barium hydroxide (ii) Aluminum nitrate + Sodium phosphate TIL Read More »

1. At STP, what volume of oxygen is needed to produce 41.8 g of carbon dioxide?;2. What volume of carbon monoxide at STP is needed to produce 701 mL of carbon dioxide?

2CO(g) + O2(g) ==> 2CO2(g) 1. At STP, what volume of oxygen is needed to produce 41.8 g of carbon dioxide?; 2. What volume of carbon monoxide at STP is needed to produce 701 mL of carbon dioxide? EXPERT ANSWER 1. At STP conditions T=273K and P=1 atm mol CO2= mass/molecular weight = 41.8/44.01 = 0.950 mol …

1. At STP, what volume of oxygen is needed to produce 41.8 g of carbon dioxide?;2. What volume of carbon monoxide at STP is needed to produce 701 mL of carbon dioxide? Read More »