Yes. Thats why you pay estimated taxes.
You will pay Self Employment tax (Scheduled SE) on a Net Profit of $400 or more on Schedule C in addition to regular income tax on it. You pay 15.3% SE tax on 92.35% of your Net Profit (If it is greater than $400). The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire.
Turbo Tax guide to Estimated taxes
A Guide to Paying Quarterly Taxes - TurboTax Tax Tips & Videos
