During compression of a spring the work done is 10 kJ and 2 kJ escaped to the surroundings as heat. The change in internal energy, `Delta U` (in kJ) is _________ .

Explanation

To find the change in internal energy (ΔU) during the compression of a spring, we can use the first law of thermodynamics, which states:

\[ \Delta U = q + w \]

Where:
- ΔU = Change in internal energy
- q = Heat exchanged (positive if absorbed by the system, negative if released)
- w = Work done on the system (positive if done on the system, negative if done by the system)

### Step-by-Step Solution:

1. **Identify the Work Done (w)**:
- The work done on the spring is given as 10 kJ.
- Since work is done on the system, we take \( w = +10 \) kJ.

2. **Identify the Heat Exchanged (q)**:
- It is given that 2 kJ of heat escaped to the surroundings.
- Since heat is released, we take \( q = -2 \) kJ.

3. **Substitute the Values into the First Law of Thermodynamics**:
- Now, we substitute the values of q and w into the equation:
\[ \Delta U = q + w \]
\[ \Delta U = (-2 \text{ kJ}) + (10 \text{ kJ}) \]

4. **Calculate ΔU**:
- Performing the arithmetic:
\[ \Delta U = -2 + 10 = 8 \text{ kJ} \]

5. **Final Result**:
- The change in internal energy, ΔU, is 8 kJ.

### Answer:
The change in internal energy, ΔU, is **8 kJ**.