The reaction between NaOH and HCl is 1:1. Therefore, to neutralize 0.5 moles of HCl, 0.5 moles of NaOH are required, which corresponds to 0.5 L of 1 M NaOH solution.

Adding a surfactant to water decreases the surface tension by disrupting the cohesive forces between water molecules.

The acceleration of the center of mass of a wheel rolling down an incline is g sin(θ).

The point of contact with the ground is momentarily at rest when the wheel rolls without slipping.

The distance traveled by the center of mass d is equal to the product of the radius R and the angle rotated θ in radians, i.e., d = Rθ.

In equilibrium, the net force acting on the object must be equal to zero.

In division, the result should have the same number of significant figures as the quantity with the least significant figures. 100.0 has 4 significant figures and 4.00 has 3 significant figures, so the result should have 3 significant figures: 25.0.

The answer should have 3 significant figures, as 25.0 has the least significant figures.

The result should have the same number of significant figures as the measurement with the least significant figures, which is 2.0 (1 significant figure).

In division, the result should have the same number of significant figures as the factor with the least significant figures. 6.022 x 10^23 has 4 significant figures and 2.0 has 2 significant figures, so the answer should have 2 significant figures.

The result should have the same number of significant figures as the measurement with the least significant figures, which is 2.5 (2 significant figures).

In multiplication, the result should have the same number of significant figures as the factor with the least significant figures. 3.00 has 3 significant figures and 2.5 has 2 significant figures, so the answer should have 2 significant figures.

The result should have 2 significant figures, as 2.5 has the least significant figures.

In multiplication, the result should have the same number of significant figures as the factor with the least significant figures. 3.00 has 3 significant figures and 2.5 has 2 significant figures, so the answer should have 2 significant figures.

The result should have 2 significant figures, as 2.5 has the least significant figures.

In multiplication, the result should have the same number of significant figures as the factor with the least significant figures. 3.24 has 3 significant figures and 2.1 has 2 significant figures, so the answer should have 2 significant figures.

Rounding to three significant figures gives 0.00457.

When rounding to three significant figures, 0.6789 becomes 0.679.

In subtraction, the result should be rounded to the least number of decimal places. 100.5 has one decimal place, so 200 - 100.5 = 99.5.

In subtraction, the result should be rounded to the least number of decimal places. 10.0 has one decimal place and 5.678 has three, so the answer should be rounded to one decimal place: 4.32 becomes 4.3.

When unpolarized light passes through a polarizer, its intensity is reduced to half of its original value.

Using the formula Vx/Vk = Lx/Lk, we have Vx = Vk * (Lx/Lk). Here, Lx = 4 m, Lk = 10 m, Vk = 12 V, thus Vx = 12 V * (4/10) = 4.8 V.

The condition for balance in a potentiometer is that the potential difference across the galvanometer must be zero, indicating that the unknown voltage is equal to the voltage across the potentiometer wire.

The circuit must be open when measuring the emf of a cell with a potentiometer to ensure that no current flows through the cell, allowing for an accurate measurement.

At balance, the potential difference across the cell equals the potential drop across the potentiometer wire.

Keeping the circuit closed ensures that the current flows properly, allowing for accurate voltage measurements.

Beryllium (Be) is the least reactive alkaline earth metal.

Barium is the most reactive alkaline earth metal due to its larger atomic size and lower ionization energy.

Beryllium is the least reactive alkaline earth metal due to its high ionization energy.

Strontium is used in fireworks to produce a red color.