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3 years ago

A student says that since the atomic theory is just a theory, it should not be considered useful. Which

Chemistry

1 answer:

Shkiper50 [21]3 years ago

8 0

Answer:

O Scientific theories are the results of many experiments and observations.

Explanation:

Going through the options;

O Scientific theories change over time.

This is true and supports the student's opinion. So wrong option!

O Scientists often do not agree about specific details of scientific theories.

This is true. However, it supports the student's opinion. So wrong option!

O Scientists often propose competing theories.

This is true. However, it supports the student's opinion. So wrong option!

O Scientific theories do not become Scientific Laws.

This is False. Theories that have withstood the test of time and countless experiments become laws. However it support's the student's opinion. So wrong option!

O Scientific theories are the results of many experiments and observations.

This is true and is against the student's opinion. This option is correct!

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What is the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper?

natali 33 [55]

Answer:

the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper is it will help you get the right answer

Explanation:

5 0

3 years ago

The effectiveness of nitrogen fertilizers depends on both their ability to deliver nitrogen to plants and the amount of nitrogen

densk [106]

Answer:

Ammonia > Urea > Ammonium nitrate > Ammonium sulphate

Explanation:

Percentage by mass of nitrogen in NH3:

Molar mass of NH3= 17 g/mol

Hence % by mass = 14/17 × 100 = 82.35%

% by mass of NH4NO3

Molar mass of NH4NO3 = 80.043 g/mol

Hence; 28/80.043 × 100 = 34.98%

% by mass of (NH4)2SO4;

Molar mass of (NH4)2SO4= 132.14 g/mol

Hence; 28/132.14 × 100 = 21.19%

% by mass of CH4N2O

Molar mass of urea = 60.0553 g/mol

Hence 28/60.0553 × 100 = 46.62%

8 0

3 years ago

Sodium hydrogen carbonate NaHCO3, also known as sodium bicarbonate or "baking soda", can be used to relieve acid indigestion. Ac

olga2289 [7]

Answer:

1.4952 grams of sodium bicarbonate she would need to ingest to neutralize this much HCl.

Explanation:

$Moles (n)=Molarity(M)\times Volume (L)$

Moles of hydrochloric acid = n

Volume of hydrochloric acid solution = 200.0 mL = 0.200 L

Molarity of the hydrochloric acid = 0.089 M

$n=0.089 M\times 0.200 L=0.0178 mol$ of HCL

$HCl(aq)+NaHCO_3(aq)\rightarrow NaCl(aq)+H_2O(l)+CO_2(g)$

According to reaction, 1 mole of HCl is neutralized by 1 mole of sodium bicarbonate.

Then 0.0178 moles of HCl wil be neutralized by :

$\frac{1}{1}\times 0.0178 mol=0.0178 mol$ of sodium bicarbonate

Mass of 0.0178 moles of sodium bicarbonate:

0.0178 mol × 72 g/mol = 1.4952 g

1.4952 grams of sodium bicarbonate she would need to ingest to neutralize this much HCl.

8 0

3 years ago

A 25.225 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 75.815 g of wa

Rudik [331]

Answer:

1.43 (w/w %)

Explanation:

HCl reacts with NH3 as follows:

HCl + NH3 → NH4+ + Cl-

<em>1 mole of HCl reacts per mole of ammonia.</em>

Mass of NH3 is obtained as follows:

<em>Moles HCl:</em>

0.02999L * (0.1068mol / L) = 3.203x10-3 moles HCl = <em>Moles NH3</em>

<em>Mass NH3 in the aliquot:</em>

3.203x10-3 moles NH3 * (17.031g / mol) = 0.0545g.

Mass of sample + water = 22.225g + 75.815g = 98.04g

Dilution factor: 98.04g / 14.842g = 6.6056

That means mass of NH3 in the sample is:

0.0545g * 6.6056 = 0.36g NH3

Weight percent is:

0.36g NH3 / 25.225g * 100

6 0

3 years ago

Describe the contributions of 3 scientists to our current understanding of the atom

bogdanovich [222]

Answer:

1. Rutherford did the scattering experiment and observed that some of the rays bounce back. He concluded that there is a mass in which positive charge is concentrated. This marks the discovery of nucleus.

2. J.J Thomson discovered electrons by conducting cathode ray experiment.

3. Dalton postulated that matter is made up of small particles caled atoms

8 0

3 years ago