The hearings are scheduled to begin on Tuesday, with testimony from Senator Jeff Sessions of Alabama, the nominee for attorney general, and Gen. John F. Kelly, the pick for homeland security secretary. On Wednesday, the parade of nominees is expected to include Rex W. Tillerson, the choice for secretary of state; Betsy DeVos, the pick for education secretary; and Representative Mike Pompeo of Kansas, the nominee to lead the C.I.A. Later in the week, the billionaire investor Wilbur L. Ross Jr., chosen as commerce secretary, and Andrew F. Puzder, the labor secretary pick, are scheduled to come before congressional panels.

While some of Mr. Trump’s nominees, notably Representative Tom Price of Georgia, the choice for health secretary and an ardent opponent of the Affordable Care Act, are certain to receive hostile receptions, large numbers of Democrats will probably vote for many others.

Still, Democrats are preparing a furious assault against the nominees by going after the president-elect himself and trying to drive a wedge between them over his most incendiary promises, like banning Muslim immigrants and bringing back torture.

“Where will they come down?” Mr. Schumer, the new Democratic leader, asked in an interview. “Will they try to persuade the president that’s the wrong way to take America?”

Democrats plan to keep the focus on the president-elect to a degree with few historical parallels. New presidents usually serve as a backdrop; this year, by contrast, Mr. Trump’s words will loom over the hearings as Democrats press the nominees to take a position on them.

Democrats have little chance of blocking any of the nominees, having given up the use of the filibuster in such cases when they were in the majority, but they say Mr. Trump has handed them ample political ammunition.

Mr. Sessions is certain to be asked whether he, as attorney general, would make good on Mr. Trump’s pledges to get a special counsel to “jail” Hillary Clinton over her email server.