A total of 0.0222 moles of NaOH are necessary to react with NH4F. \nBased on the reaction NH4F + NaOH --> NaF + NH3 + H2O, we start with: \nMass of NH4F = 0.821 g, NaOH concentration = 1 M, volume of NaOH = 25 mL. \nTo find moles: moles of NaOH = (CV)/1000. Thus, moles of NaOH = (1 * 25)/1000 = 0.025 moles of NaOH used. \nThe molar mass of NH4F is 37 g/mol, making moles of NH4F = 0.821 / 37 = 0.0222 moles. \nThis shows that NaOH is in excess, with 0.025 - 0.0222 = 0.0028 moles of NaOH remaining. Hence, 0.0222 moles of NaOH are needed to react with NH4F.
First scenario:
IV: soda, gatorade, orange juice, and water
DV: state of the liquids listed above
Control: freezer and ice tray
Second scenario:
IV: laundry detergent, water
DV: cleanliness of the squares post-wash
Control: chocolate, cloth type, cloth squares
Third scenario:
IV: type of water used, pea plant
DV: growth of the pea plant
Control: pots and daily water amount for the plant
Response:
H₂SO₄
Clarification:
Given a compound consisting of 0.475 g H, 7.557 g S, and 15.107 g O, we must compute the empirical formula by following specific steps.
Step 1: Compute the total mass of the compound
Total mass = mass H + mass S + mass O = 0.475 g + 7.557 g + 15.107 g
Total mass = 23.139 g
Step 2: Determine the percentage composition.
H: (0.475g/23.139g) × 100% = 2.05%
S: (7.557g/23.139g) × 100% = 32.66%
O: (15.107g/23.139g) × 100% = 65.29%
Step 3: Divide each percentage by the element's atomic mass
H: 2.05/1.01 = 2.03
S: 32.66/32.07 = 1.018
O: 65.29/16.00 = 4.081
Step 4: Normalize all values by the smallest one
H: 2.03/1.018 ≈ 2
S: 1.018/1.018 = 1
O: 4.081/1.018 ≈ 4
Thus, the empirical formula for the compound is H₂SO₄.
Answer:
A, B, and C
Explanation:
Indeed, atoms possess mass and serve as the fundamental building blocks of chemical elements. While matter is composed of atoms, these particles themselves do not occupy physical space.
Atoms consist mostly of void, which excludes them from the other responses.
This confirms that A, B, and C are the right choices.
