Answer:
The answer is B. A rolling skateboard slows down because some of its kinetic energy changes to heat.
Explanation:
The law of conservation says energy cant be created or destroyed .Which basically eliminates all of them except b. It can only be transferred
Answer:
We need 1.1 grams of Mg
Explanation:
Step 1: Data given
Volume of water = 78 mL
Initial temperature = 29 °C
Final temperature = 78 °C
The standard heats of formation
−285.8 kJ/mol H2O(l)
−924.54 kJ/mol Mg(OH)2(s)
Step 2: The equation
The heat is produced by the following reaction:
Mg(s)+2H2O(l)→Mg(OH)2(s)+H2(g)
Step 3: Calculate the mass of Mg needed
Using the standard heats of formation:
−285.8 kJ/mol H2O(l)
−924.54 kJ/mol Mg(OH)2(s)
Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g)
−924.54 kJ − (2 * −285.8 kJ) = −352.94 kJ/mol Mg
(4.184 J/g·°C) * (78 g) * (78 - 29)°C = 15991.248 J required
(15991.248 J) / (352940 J/mol Mg) * (24.3 g Mg/mol) = 1.1 g Mg
We need 1.1 grams of Mg
It would take 8 antacid tablets to produce 120 mL of CO2 gas.
Answer:
Nickel and Titanium
Explanation:
Nitinol is an alloy of Nickel and Titanium. It posesses two properties such that,
- The shape memory effect
- Super elasticity
Shape memory is the ability of nitinol to undergo deformation at one temperature, stay in its deformed shape when the external force is removed.
Superelasticity is the ability for the metal to undergo large deformations and immediately return to its undeformed shape upon removal of the external load.
Hence, the correct option is (b) "Nickel and Titanium".
