Please help I will give ALOT OF BRAINLY POINTS!!!!!

1. Mutations occur when the DNA does not copy itself correctly. Mutations are

Agata [3.3K]

1 is D 2 is c 3 is A and 4 the nucleus is so big because it is one of our largest cells in our body... hope this helps!!!!!!!!!!!

4 0

3 years ago

A student is instructed to make 1 L of a 2.0 M solution of CaCl2 using dry salt. How should he do this?

Pachacha [2.7K]

The student should follow following steps to make 1 L of 2.0 M CaCl₂.

1. First he should calculate the number of moles of 2.0 M CaCl₂ in 1 L solution.

Molarity of the solution = 2.0 M
Volume of solution which should be prepared = 1 L

Molarity = number of moles / volume of the solution

Hence, number of moles in 1 L = 2 mol

2. Find out the mass of dry CaCl₂ in 2 moles.

moles = mass / molar mass

Moles of CaCl₂ = 2 mol
Molar mass of CaCl₂ = 110.98 g/mol

Hence, mass of CaCl₂ = 2 mol x 110.98 g/mol
= 221.96 g

3. Weigh the mass accurately

4. Then take a cleaned and dry1 L volumetric flask and place a funnel top of it. Then carefully add the salt into the volumetric flask and finally wash the funnel and watch glass with de-ionized water. That water also should be added into the volumetric flask.

5. Then add some de-ionized water into the volumetric flask and swirl well until all salt are dissolved.

6. Then top up to mark of the volumetric flask carefully.

7. As the final step prepared solution should be labelled.

4 0

3 years ago

A chemist dissolves 240mg of pure barium hydroxide in enough water to make up of solution. Calculate the pH of the solution. (Th

goblinko [34]

Answer:

pH = 12.22

Explanation:

... To make up 170mL of solution... The temperature is 25°C...

The dissolution of Barium Hydroxide, Ba(OH)₂ occurs as follows:

Ba(OH)₂ ⇄ Ba²⁺(aq) + 2OH⁻(aq)

Where 1 mole of barium hydroxide produce 2 moles of hydroxide ion.

To solve this question we need to convert mass of the hydroxide to moles with its molar mass. Twice these moles are moles of hydroxide ion (Based on the chemical equation). With moles of OH⁻ and the volume we can find [OH⁻] and [H⁺] using Kw. As pH = -log[H⁺], we can solve this problem:

Moles Ba(OH)₂ molar mass: 171.34g/mol

0.240g * (1mol / 171.34g) = 1.4x10⁻³ moles * 2 =

2.80x10⁻³ moles of OH⁻

Molarity [OH⁻] and [H⁺]

2.80x10⁻³ moles of OH⁻ / 0.170L = 0.01648M

As Kw at 25°C is 1x10⁻¹⁴:

Kw = 1x10⁻¹⁴ = [OH⁻] [H⁺]

[H⁺] = Kw / [OH⁻] = 1x10⁻¹⁴/0.01648M = 6.068x10⁻¹³M

pH:

pH = -log [H⁺]

pH = -log [6.068x10⁻¹³M]

8 0

3 years ago

If 25.0 g NO are produced, how many grams of nitrogen gas are used?

ivanzaharov [21]

Based on the assumption that the reaction involves N and O to produce NO, if 25.0 g of NO are produced, the amount of N gas used would be 11.66 grams

<h3>Stoichiometric calculation</h3>

From the equation of the reaction:

N + O ---------> NO

Mole ratio of N to NO is 1:1

Mole of 25.0 g of NO = 25/30.01 = 0.833 moles

Equivalent mole of N = 0.833 moles

Mass of 0.833 moles N = 0.833 x 14 = 11.66 grams

More on stoichiometric calculations can be found here: brainly.com/question/8062886

7 0

2 years ago

Arbon dioxide is dissolved in blood (ph 7.5) to form a mixture of carbonic acid and bicarbonate. Part a neglecting free co2, wha

Aleks04 [339]

Answer : The fraction of carbonic acid present in the blood is 5.95%

Explanation :

The mixture consists of carbonic acid ( H₂CO₃) and bicarbonate ion ( HCO₃⁻). This represents a mixture of weak acid and its conjugate which is a buffer.

The pH of a buffer is calculated using Henderson equation which is given below.

$pH = pKa + log \frac{[Base]}{[Acid]}$