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3 years ago

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Which of the following statements about the nucleus is false? A. Able to be lost or gained in chemical reactions. B. Made up of

protons an neutrons. C. None of these D. Contains nearly all of the mass of the atom.

1 answer:

vlabodo [156]3 years ago

7 0

Answer:

A. Able to be lost or gained in chemical reactions.

Explanation:

Only electrons are lost or gained.

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Are there any parts of the human body that get oxygen directly from the air and not from the blood?

n200080 [17]

Answer: Cornea

Explanation: The cornea is the only part of a human body that has no blood supply as it gets oxygen directly through the air.

3 0

3 years ago

Calculate in gramm the mass of 0.1 mole of hydrochloric acid(h=1 ,cl=35.5)

babunello [35]

Answer:

mass of HCl = 3.65 g

Explanation:

Data Given:

Moles of hydrochloric acid HCl = 0.1 mole

Mass in grams of hydrochloric acid HCl = ?

Solution:

Mole Formula

no. of moles = Mass in grams / molar mass

To find Mass in grams rearrange the above Formula

Mass in grams = no. of moles x molar mass . . . . . . . (1)

Molar mass of HCl = 1 + 35.5 = 36.5 g/mol

Put values in equation 1

Mass in grams = 0.1 mole x 36.5 g/mol

Mass in grams = 3.65 g

mass of HCl = 3.65 g

6 0

3 years ago

Combustion of coal releases sulfur dioxide into the atmosphere. The following process converts this gas into sulfuric acid, a co

Usimov [2.4K]

Answer:

$m=7.07gH_{2}SO_{4}$

Explanation:

1. Take in account the sulfuric acid at STP:

$1840\frac{g}{L}$

2. Density is expressed as the ratio between the mass and the volume of a substance so:

$d=\frac{m}{V}$

Solving for m:

$m=\frac{V}{d}$

3. Replace values:

$m=\frac{1.30*10^{4}L}{1840\frac{g}{L}}$

$m=7.07gH_{2}SO_{4}$

4 0

3 years ago

What is the scientific method describes as nonlinear

Phoenix [80]

Scientists often repeat one or more steps several times.

8 0

3 years ago

25 mL of 0.10 M aqueous acetic acid is titrated with 0.10 M NaOH(aq). What is the pH after 30 mL of NaOH have been added?

weeeeeb [17]

Answer:

pH = 11.95≈12

Explanation:

Remember the reaction among aqueous acetic acid ( $CH_3COOH$ ) and aqueous sodium hydroxide (NaOH)

$CH_3COOH + NaOH -> CH_3COONa + H_2O$

First step. Need to know how much moles of the substances are present

$0.1 \frac{mol NaOH}{L} * 0.030 L = 0.003 mol NaOH[tex]0.1 \frac{mol CH_3COOH}{L} * 0.025 L= 0.0025 mol CH_3COOHSecond step. Know wich substance is in excess.0.0025 mol CH_3COOH * [tex]1 mol NaOH/ 1 mol CH_3COOH$ = 0.0025 mol NaOH

0.003 mol NaOH * $1 mol CH_3COOH$ / 1 mol NaOH = 0.003 mol CH_3COOH[/tex]

NaOH is in excess. Now, how much?

0.003 mole NaOH - 0.0025 mole NaOH = 0.0005 mole NaOH

Then, that amount in excess would be responsable for the pH.

Third step. Know the pH

Remember that pH= -log[H+]

According to the dissociation of water equilibrium

Kw=[H+]*[OH-]= 10^(-14)

The dissociation of NaOH is

NaOH -> $Na^{+} + OH^{-}$

Now, concentration of OH^{-}[/tex] would be given for the excess of NaOH.

[OH-]= 0.0005 mole / 0.055 L = 0.00909 M

Careful: we have to use the total volumen

Les us to calculate pH

$pH= -log [H+]\\pH= -log \frac{K_w}{[OH-]} \\pH= 11.95$

6 0

3 years ago