Form 1120-S, Business Expenses:

As both of these items have a useful life longer than 1 year, they are generally considered fixed assets with multi-year depreciation expense; but you do have a few options to expense their full cost immediately on your 2025 return.
 

1. You can make the De Minimis Safe Harbor Election to immediately expense asset purchases <$2,500 in cost. This election is found when prompted in the Business Assets interview questions, if assets were purchased during the year at <$2,500 - answer Yes. 
   • See: TurboTax - What can I expense or depreciate with the business safe harbor election? 
2. The office chair is furniture which is considered to have a 7-year depreciable life; for 2025, it qualifies for the 100% bonus depreciation deduction (IRS Sec. 168(k)). Enter the chair details into the Business Assets menu (using Step-by-Step), and you will then be prompted whether to elect 100% bonus depreciation on this asset. Saying Yes to the election will allow you to expense the full cost of the chair on this year's tax return.
   1. Note: this election will then be required for all assets placed in service this year in this class life (7-year property). 
3. The mobile A/C unit is 5-year personal property, and qualifies for either 100% bonus depreciation or Section 179 treatment - both allowing you to expense the full cost in the first year the asset is placed in service. Enter the Business Asset details as usual, and the software will prompt you to make an election for 100% bonus depr. or Sec. 179. 
   • Note: if choosing bonus, you will need to make the same election for all 5-year property. 

Additional references:
TurboTax - What's a Section 179 deduction?
IRS - Interim Guidance on 100% Bonus Depreciation