Answer:
A
Explanation:
because B is wrong as it doesn't have the same mass number. C is wrong as it has different number of neutrons. D is wrong as it has more neutrons than protons.
GEORGEOCTOBER 18, 2012Floor Wax is Harmful to the Environment
Floor wax is applied on floor surfaces to make it scuff-resistant, water-resistant, slip resistant and glossy. It provides a thin, protective and hard surface layer when applied to flooring. Conventional floor wax has five main ingredients and each one of them has detrimental effects on the environment, not to mention the chemical waste created by the continuous upkeep required. The cumulative effects of these ingredients on the environmental render their harmful actions more potent and difficult to reverse.
<span>The surface area is 109.3 square centimeters or 0.01093 square meters. The area formula requires that we use the radius of the disc. We can find the radius by diving the diameter by 2, so radius = 11.8/2 or 5.9 cm. We can use 3.14 as an approximation for π. The surface area is 3.14 * (5.9*5.9).
Since the diameter is given in cm, the surface area units are in square centimeters. To convert to meters, divide any measurement in centimeters by 100, but we need to convert to "square" meters, so we need to divide our square centimeters by 100 * 100, or by 10,000. Dividing 109.3 by 10,000 results in 0.01093 square "meters".</span>
Answer:
1.36 × 10³ mL of water.
Explanation:
We can utilize the dilution equation. Recall that:

Where <em>M</em> represents molarity and <em>V</em> represents volume.
Let the initial concentration and unknown volume be <em>M</em>₁ and <em>V</em>₁, respectively. Let the final concentration and required volume be <em>M</em>₂ and <em>V</em>₂, respectively. Solve for <em>V</em>₁:

Therefore, we can begin with 0.640 L of the 2.50 M solution and add enough distilled water to dilute the solution to 2.00 L. The required amount of water is thus:

Convert this value to mL:

Therefore, about 1.36 × 10³ mL of water need to be added to the 2.50 M solution.