How many joules are required to raise the temperature of 450mL of water from 30 °C to 100 °C?
The specific heat of copper metal is 0.385 J/ g- K. How many KJ of heat needed to raise the temperature of 1.1 kg block of copper from 27.5 C to 50 C?
If 200 J of heats is added to 25 g of iron at a temperature of 15 °C, what will be the final temperature?
A hot piece of iron with a mass of 75g and a temperature of 200 °C, is dropped into 250g of cool water at a temperature of 18° C. What is the final temperature of the water and the iron?
When 1.00g of sodium hydroxide is dissolved in 100 g of water in an insulated container the temperature rises from 20.0° C to 22.66° C. Calculate the enthalpy for the solution. State by assumptions made.
Calculate change in enthalpy when 100 mL of 1.0 mole/dm NaOH is added to 100 mole/dm HCl in an insulated container the temperature rises from 21.0° C to 34.6 °C.
How much heat will release when 6.44g of sulfur reacts with excess O2 according to the following equation?
2 S + 3 O2 > 2 S 3 H = -791.4 KJ
How much heat will be absorbed when 38.2g of bromine reacts with excess H2 according to the following equation?
H2 + Br2 > 2 HBr H= 72.80 KJ
An experiment was carried was carried out to determine the amount of energy released in a low fat chocolate bar with a the mass 50.0g. the complete combustion of a 10.0 g of the bar raised the temperature of 500.0g of water from 19.0° C to 86.5 °C. calculate the energy value ( KJ )of the chocolate bar.
How much heat will be transferred when 5.81g of graphite reacts with excess hydrogen according to the following reaction? Is this reaction endothermic or exothermic?
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To calculate the amount of heat required or released in each of the given scenarios, we can use the formula:
Q = mcΔT
where:
Q is the heat energy in joules (J),
m is the mass in grams (g),
c is the specific heat capacity in J/g°C, and
ΔT is the change in temperature in degrees Celsius (°C).
Let's calculate the required values step-by-step for each scenario:
1. How many joules are required to raise the temperature of 450mL of water from 30 °C to 100 °C?
First, we need to convert the volume of water to its mass since the specific heat capacity is given in J/g°C.
The density of water is approximately 1 g/mL, so the mass of 450mL water is 450g.
ΔT = (100 °C - 30 °C) = 70 °C
Using the formula:
Q = mcΔT
Q = (450g) * (4.18 J/g°C) * (70 °C)
Q = 132,930 J
Therefore, 132,930 joules of heat are required to raise the temperature of 450mL of water from 30 °C to 100 °C.
2. How many KJ of heat are needed to raise the temperature of a 1.1 kg block of copper from 27.5 °C to 50 °C?
ΔT = (50 °C - 27.5 °C) = 22.5 °C
Using the formula:
Q = mcΔT
Q = (1100g) * (0.385 J/g°C) * (22.5 °C)
Q = 941.625 J
To convert to KJ:
Q = 941.625 J / 1000
Q = 0.941625 KJ
Therefore, 0.941625 KJ of heat are needed to raise the temperature of a 1.1 kg block of copper from 27.5 °C to 50 °C.
3. If 200 J of heat is added to 25g of iron at a temperature of 15 °C, what will be the final temperature?
We can rearrange the formula to solve for ΔT:
ΔT = Q / (mc)
ΔT = 200J / (25g * 0.449 J/g°C) [The specific heat capacity of iron is approximately 0.449 J/g°C.]
ΔT = 8.890 °C
To calculate the final temperature:
Final temperature = Initial temperature + ΔT
Final temperature = 15 °C + 8.890 °C
Final temperature = 23.890 °C
Therefore, the final temperature would be 23.890 °C.
I will provide answers to the remaining questions in the next response.
To find the answers to these questions, we'll need to use the equations related to heat transfer and specific heat capacity. Here's how to approach each problem:
1. To calculate the heat energy required to raise the temperature of water, you can use the formula:
q = m x c x ΔT
where q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.
2. For the copper block, the same formula can be used with the given specific heat capacity:
q = m x c x ΔT
Convert the units if necessary.
3. To find the final temperature of iron, use the equation:
q = m x c x ΔT
Rearrange the equation and solve for ΔT, then add it to the initial temperature.
4. For the iron and water mixture problem, use the principle of conservation of energy:
Heat lost by iron = Heat gained by water
m1 x c1 x ΔT1 = m2 x c2 x ΔT2
Rearrange the equation and solve for ΔT2.
5. To calculate the enthalpy for the sodium hydroxide solution, use the equation:
q = m x c x ΔT
The specific heat capacity of water is usually used as an approximation for the solution's specific heat capacity.
6. For the NaOH and HCl reaction, use the same equation as before:
q = m x c x ΔT
Adjust the units and convert from moles to grams if necessary.
7. To calculate the heat released during the sulfur reaction, use the given enthalpy change value:
q = ΔH
Convert the units if necessary.
8. For the bromine reaction, use the same equation as before:
q = ΔH
Adjust the units and convert from moles to grams if necessary.
9. For the chocolate bar energy value, use the equation:
q = m x c x ΔT
Convert the initial temperature to Kelvin and adjust the units.
10. Lastly, for the graphite reaction, use the equation:
q = ΔH
Determine if the sign of ΔH is negative for an exothermic reaction or positive for an endothermic reaction.
By applying these formulas and concepts, you should be able to find the answers to the given questions.