Please Help Chemistry

Question

1-If a sample of a gas at 32 oC has a pressure of 1.92 atm, what will its pressure be at 78 oC?

2-The % concentration by mass of a solution prepared by dissolving 26.4 g of NaBr in 415 g of solution is:

3-The answer, in scientific notation, to the calculation

(4.3 x 10 4) / (2.9 x 10 -3) is:

4-Given the reaction: HPO 4 2- + HCl ←→ H 2PO 4 - + Cl -, the Bronsted-Lowry base in the forward reaction is:

5-The number of moles of oxygen that react with 4.65 moles of aluminum according to the equation 4 Al + 3 O 2 → 2 Al 2O 3 is:

6-The number of grams of aluminum that will react with 2.55 moles of hydrochloric acid according to the reaction

2 Al + 6 HCl → 2 AlCl 3 + 3 H 2 is:

Answer 1

In the future, You should probably break these up to individual questions, or limit them to 2 or 3 question per post. I'll give you advice on how to do them, and you can actually carry out the procedure.

1). P1/T1 = P2/T2 with T in Kelvin; 1.02 atm/305K = P2/351K => answer in atm

2). %by mass = mass of solute/total mass(x100%) = 26.4 g / (26.4 g + 415 g) [x100%] = % by mass NaBr

3). 4.3x10⁴ x 2.9x10^-3 = 12.47x10¹ = 1.247x10² = 1.2x10² (2 sig.figs.)

4). BL base is one that accepts H+, so it would be HPO₄^2-

5). 4.65 mol Al x 3 mol O₂ / 4 mol Al = moles O₂ needed

6). 2.55 mol HCl x 2 mol Al / 6 mol HCl x 27 g Al/mol Al = g Al needed