Answer:
True
Explanation:
Messelson and strahl explain the semiconservative existence of DNA replication by using CsCl gradient centrifugation. The hardest would go and rest at the base of the test tube, while the lightest would be at the top, the lightest would find a position between the heavy and the lightest. When the heavy tube is centralized, from a pool of light, bulky and moderate DNA.
This technique is called density-gradient centrifugation. Hence, the given statement is true.
Answer:
The drinks that the student should avoid - if he wants to avoid damage to his teeth - are drinks C and E, since they are acidic, according to their pH.
Explanation:
pH measures the acidity or alkalinity of a solution, taking into account the amount of hydrogen ions present in it, and established on a scale that goes from 0 to 14.
In chemistry, pH is derived from the formula that indicates:
<em>pH = - Log₁₀ αH⁺</em>
, where α is the activity of hydrogen ions.
A solution with a pH of 7 is considered neutral, above this value it is an acidic solution and below this value it is called acidic.
According to this:
- <em>Acidic drinks are: drink C (5.3) and E (2.4).</em>
- <em>The basic drinks are: drink A (11.9) and drink D (9.8).</em>
- <em>The neutral drink is the drink B (7), which corresponds to water.</em>
Answer:
these atoms are stable because a stable atom has a net charge of 0. In other words, it has an equal number of protons and electrons. The positive protons cancel out the negative electrons. In this question they mention that the number of electrons is 8, now if we see the proton/atomic number of oxygen, it is also 8. Therefore, the net charge becomes zero and hence the atoms are stable.
hope that helps..
Charles law gives the relationship between temperature and volume of gas.
It states that at a constant pressure, volume of gas is directly proportional to the temperature for a fixed amount of gas.
V/T = constant
where V- volume, T- temperature
V1/T1 = V2/T2
Where parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
temperature should be in Kelvin for calculation
temperature in K = temperature in Celcius + 273
T1 = 137 °C + 273 = 410 K
substituting values in the equation
250 mL / 410 K = 425 mL /T2
T2 = 697 K
temperature in Celcius = 697 K - 273
temperature = 424 °C
