Section II - Short Answer Response (8 marks) will!) 21. How much energy is required to increase the temperature of 750.0 g of seawater by 30.0^circ C square 22. How much thermal energy is required to melt 4.525 mol mol of ice 0.0^circ C to liquid water at 0.0^circ C : square 23. What is the specific heat capacity of a substance if it requires 2334 J of energy to change the temperature of 40.0 g of the substance by 15^circ C ? Section III: Long Answer Response (8 marks) 24. Describe the greenhouse effect and how it both positively and negatively affects Earth's delicate radiation budget. square 2

**21.** To calculate the energy required, we use the formula:<br /><br />Q = mcΔT<br /><br />Where:<br />* Q = energy (Joules)<br />* m = mass (grams) = 750.0 g<br />* c = specific heat capacity of seawater (approximately 4.18 J/g°C - slightly lower than pure water due to salt content)<br />* ΔT = change in temperature (°C) = 30.0°C<br /><br />Q = (750.0 g) * (4.18 J/g°C) * (30.0°C)<br />Q = 94050 J<br /><br />**Answer:** 94050 J (or 94.1 kJ)<br /><br /><br />**22.** To calculate the thermal energy required to melt the ice, we use the molar enthalpy of fusion:<br /><br />Q = nΔH_fus<br /><br />Where:<br />* Q = energy (Joules)<br />* n = moles = 4.525 mol<br />* ΔH_fus = molar enthalpy of fusion of ice (6.01 kJ/mol)<br /><br />Q = (4.525 mol) * (6.01 kJ/mol)<br />Q = 27.2 kJ<br /><br />**Answer:** 27.2 kJ<br /><br /><br />**23.** To calculate the specific heat capacity, we rearrange the formula Q = mcΔT:<br /><br />c = Q / (mΔT)<br /><br />Where:<br />* c = specific heat capacity (J/g°C)<br />* Q = energy (Joules) = 2334 J<br />* m = mass (grams) = 40.0 g<br />* ΔT = change in temperature (°C) = 15°C<br /><br />c = 2334 J / (40.0 g * 15°C)<br />c = 3.89 J/g°C<br /><br />**Answer:** 3.89 J/g°C<br /><br /><br />**24.** The Greenhouse Effect: A Balancing Act for Earth's Temperature<br /><br />The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. These gases, such as carbon dioxide, methane, nitrous oxide, and water vapor, trap heat in the atmosphere, much like the glass roof of a greenhouse. This trapped heat keeps the Earth warm enough to support life.<br /><br />**Positive Effects:**<br /><br />* **Habitable Temperature:** Without the greenhouse effect, Earth's average temperature would be significantly colder, making it uninhabitable for most life forms as we know them. The greenhouse effect maintains a temperature range suitable for liquid water, a crucial component for life.<br /><br />**Negative Effects:**<br /><br />* **Global Warming and Climate Change:** Human activities, primarily the burning of fossil fuels (coal, oil, and natural gas) and deforestation, have increased the concentration of greenhouse gases in the atmosphere. This enhanced greenhouse effect traps more heat, leading to a gradual warming of the planet, known as global warming. This warming trend drives climate change, resulting in a cascade of negative consequences, including:<br /> * **Rising Sea Levels:** Melting glaciers and thermal expansion of water contribute to rising sea levels, threatening coastal communities and ecosystems.<br /> * **Extreme Weather Events:** Increased frequency and intensity of heatwaves, droughts, floods, storms, and wildfires.<br /> * **Disruptions to Ecosystems:** Changes in temperature and precipitation patterns disrupt ecosystems, affecting plant and animal life.<br /> * **Ocean Acidification:** Increased CO2 in the atmosphere is absorbed by the oceans, leading to a decrease in pH, which harms marine life, particularly shellfish and coral reefs.<br /><br /><br />In essence, the greenhouse effect is essential for life on Earth, but human activities have amplified it, leading to detrimental consequences. Addressing this imbalance requires global efforts to reduce greenhouse gas emissions and transition to more sustainable practices.<br />