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1 year ago

Select the correct answer from each drop-down menu.

1 answer:

5 0

A scientists is scientific knowledge established through direct observation and remains constant. Scientific knowledge can change with facts and conduct of experiment.

<h3>What happens to scientific knowledge as it becomes older?</h3>

Scientific theories that have been accepted for a long time may change throughout time. Changes in societal, political, or religious ideas could occur together with new scientific discoveries. To obtain a deeper understanding, students should perform historical research on the era when scientific theories were developed.

<h3>What needs to happen for science to advance?</h3>

Observations and supporting data are the basis of scientific understanding. It could change as new facts and observations are discovered. Examining recent discoveries will advance science.

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What is the energy required to go from a solid to a liquid called?

jek_recluse [69]

Answer:

C. The thermal energy of a substance.

Explanation:

Hope it helps.

3 0

3 years ago

Urea (CH4N2O) is a common fertilizer that can be synthesized by the reaction of ammonia (NH3) with carbon dioxide as follows: 2N

Montano1993 [528]

The question is incomplete, here is the complete question:

Urea (CH₄N₂O) is a common fertilizer that can be synthesized by the reaction of ammonia (NH₃) with carbon dioxide as follows: 2NH₃(aq) + CO₂(aq) → CH₄N₂O(aq) + H₂O(l) In an industrial synthesis of urea, a chemist combines 135.9 kg of ammonia with 211.4 kg of carbon dioxide and obtains 178.0 kg of urea.

Determine the limiting reactant. (express your answer as a chemical formula)

<u>Answer:</u> The limiting reactant is ammonia $(NH_3)$

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

<u>For ammonia:</u>

Given mass of ammonia = 135.9 kg = 135900 g (Conversion factor: 1 kg = 1000 g)

Molar mass of ammonia = 17 g/mol

Putting values in equation 1, we get:

$\text{Moles of ammonia}=\frac{135900g}{17g/mol}=7994.12mol$

<u>For carbon dioxide gas:</u>

Given mass of carbon dioxide gas = 211.4 kg = 211400 g

Molar mass of carbon dioxide gas = 44 g/mol

Putting values in equation 1, we get:

$\text{Moles of carbon dioxide gas}=\frac{211400g}{44g/mol}=4804.54mol$

The given chemical reaction follows:

$2NH_3(aq.)+CO_2(aq,)\rightarrow CH_4N_2O(aq.)+H_2O(l)$

By Stoichiometry of the reaction:

2 moles of ammonia reacts with 1 mole of carbon dioxide

So, 7994.12 moles of ammonia will react with = $\frac{1}{2}\times 7994.12=3997.06mol$ of carbon dioxide

As, given amount of carbon dioxide is more than the required amount. So, it is considered as an excess reagent.

Thus, ammonia is considered as a limiting reagent because it limits the formation of product.

Hence, the limiting reactant is ammonia $(NH_3)$

5 0

3 years ago

HELP ASAP PLEASE<br> Use the word Precision in a sentence relating to chemistry!

Leno4ka [110]

Answer:

I needed to use good precision in my measurement for my chemistry lab

Explanation:

7 0

3 years ago

I NEED HELP PLEASEEEEEE I WILL RATE BRAINLIEST!!!!

MrRa [10]

<span>0.002 moles is the answer </span>

8 0

3 years ago

All of the statements describe hydrogen bonds EXCEPT: a. Hydrogen bonds account for the anomalously high boiling point of water.

Mamont248 [21]

Answer:

The correct option is e

Explanation:

Hydrogen bond is an intermolecular interaction/bonding that are formed between an electronegative atom (such as nitrogen, oxygen and fluorine) and a hydrogen atom. They are weak intermolecular bonds compared to covalent bonds but account for the high boiling point of water because of the strong hydrogen bond presence between the water molecules. Water molecules form hydrogen bonds between each other; since an oxygen atom (in a water molecule) has two lone pairs on it's outermost shell, it forms an hydrogen bond with two hydrogen atoms of other water molecule. Due to the fluidity of liquid water molecules, hydrogen bonds keep getting broken (although recreated/formed almost immediately), hence, individual hydrogen bonds in liquid water does not exist for long.

In the explanation above, it was stated that the strength of the hydrogen bond in water is the reason for it's high boiling point. The atoms in a water molecule are bent NOT linear hence the strength of hydrogen bond does not depend on the linearity of the atoms involved in the bond.

3 0

3 years ago