金属的比热容

比较铝、铜和铁的热容

Thermochemistry Intermediate (High School) 40 分钟 ~$10.00

目标

用混合法测定几种金属的比热容，并与公认值进行比较。

背景

The specific heat capacity of a metal can be determined by heating a known mass of metal to a known temperature, then transferring it to water in a calorimeter and measuring the temperature change. Energy conservation (q_metal = -q_water) allows calculation of the metal's specific heat.

安全警告

  • Hot metals and boiling water — burn risk
  • Use tongs to transfer hot metals
  • Do not touch hot metals with bare hands

所需PPE

goggles lab_coat

材料

  • Metal samples (Al, Cu, Fe) (50 g each)
    Cylindrical pieces work best
  • Distilled water (300 mL)
  • Boiling water (500 mL)
    For heating metals

设备

Polystyrene cup calorimeter Beaker (600 mL) Hot plate Thermometer (2) Analytical balance Tongs String

步骤

1

Weigh each metal sample accurately. Record masses.

3 分钟
2

Place all metals in boiling water for 10 minutes to reach 100°C.

12 分钟 Handle hot water carefully
3

Add 100 mL room-temperature water to the calorimeter. Record initial temperature.

2 分钟
4

Using tongs, quickly transfer the aluminum sample to the calorimeter. Stir and record max temperature.

5 分钟 Hot metal — use tongs
5

Calculate c(Al) = m(water)×c(water)×ΔT(water) / [m(Al)×ΔT(Al)].

5 分钟
6

Repeat steps 3-5 for copper and iron.

15 分钟
7

Compare measured values with accepted: Al=0.897, Cu=0.385, Fe=0.449 J/g°C.

5 分钟

预期结果

Aluminum should give the largest temperature rise in the water (highest specific heat), followed by iron, then copper. Measured values should be within 10-20% of accepted values.

清理

Allow metals to cool completely. Dry and store. Pour water down the drain. Clean calorimeter.

详情

类别
Thermochemistry
难度
Intermediate (High School)
时长
40 分钟
预估费用
$10.00
步骤数
7
材料
3

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Frequently Asked Questions

What is the objective of 金属的比热容?
用混合法测定几种金属的比热容，并与公认值进行比较。
How difficult is 金属的比热容?
This experiment is rated as Intermediate (High School). It takes approximately 40 minutes to complete.
What safety precautions are needed for 金属的比热容?
Key safety precautions include: Hot metals and boiling water — burn risk; Use tongs to transfer hot metals; Do not touch hot metals with bare hands.
What materials are needed for 金属的比热容?
The main materials required are: Metal samples (Al, Cu, Fe), Distilled water, Boiling water.
What results should I expect from 金属的比热容?
Aluminum should give the largest temperature rise in the water (highest specific heat), followed by iron, then copper. Measured values should be within 10-20% of accepted values.