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3 years ago

Which substance can not be broken down by a chemical change? silicon propane ethane water

Chemistry

2 answers:

babunello [35]3 years ago

5 0

I think the answer is silicon :))

navik [9.2K]3 years ago

5 0

Answer:

$\huge \boxed{\mathrm{silicon}}$

Explanation:

Silicon cannot be broken down by any physical or chemical methods, because it is an element. It has properties of an element nor a compound or mixture.

Silicon is a chemical element with the symbol Si and atomic number 14.

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You can decide if a paint booth filter is hazardous waste by answering which of the following questions:

BaLLatris [955]

Answer: (D) Are there solvents mixed in (or is it water based)?

3 0

3 years ago

How many molecules are in 3.6 grams of NaCl?

raketka [301]

Answer:

$\boxed{\text{None}}$

Explanation:

There are no molecules in NaCl, because it consists only of ions.

However, we can calculate the number of formula units (FU) of NaCl.

Step 1. Calculate the moles of NaCl

$\text{No. of moles}=\text{3.6 g NaCl}\times \dfrac{\text{1 mol NaCl}}{\text{63.54 g NaCl}} = \text{0.0567 mol NaCl}$

Step 2. Convert moles to formula units

$\text{FU} = \text{0.0567 mol NaCl} \times \dfrac{6.022 \times 10^{23}\text{ FU NaCl}}{\text{1 mol NaCl}}\\\\= 3.4 \times 10^{22} \text{ FU NaCl}$

There are $\boxed{3.4 \times 10^{22} \text{ FU NaCl}}$ in 3.6 g of NaCl.

6 0

3 years ago

Someone please help me!!!!!!!

Tresset [83]

Answer:

Hydrogen Chloride Gas is heavier than air and sinks to the ground after being released. Firefighters closer to the ground will be subjected to significantly greater concentrations of hydrogen chloride gas than the firefighters walking on top of railcars.

Explanation:

The molar mass of air is 28.97 g/mol. Air is approximately 78% N2, which has a molar mass of 28.014 g/mol and 21% oxygen, which has a molar mass of 32 g/mol; the remaining constituents of air include CO2 and other trace amounts of gases.

The molar mass of HCl is 36.458 g/mol.

Because HCl is heavier than air, it sinks toward the ground, displacing the lighter air.

The height of railway cars is reported to vary between 13.5 ft to 15.5 ft. So firefighters on tank cars are generally above the HCl gas (although localized atmospheric conditions could cause the HCl to move higher up in the air column).

5 0

3 years ago

How does heat move between objects that are touching?

Tom [10]

Answer:

Conduction

Explanation:

Conduction is heat transfer between two objects that are touching each other. When two objects touch and one has a higher temperature than the other; heat is transferred to the object with the lower temperature. ... In radiation, heat is transferred from one object to another by electromagnetic waves of energy. Edit : Please mark brainliest if it helped, thanks.

6 0

2 years ago

. Explain why some desert animals excrete uric acid rather than ammonia. (2 marks)

avanturin [10]

Answer:

AFAIK

Explanation:

uric acid is much less toxic than ammonia, hence bigger concentrations of it are tolerated in the body. This means you can excrete it while excreting very little water - beneficial wherever water's not abundant.

There's a tradeoff though, uric acid requires more energy to synthesize than ammonia, so pretty much all fish, say, excrete ammonia rather than uric acid - it's no problem to dilute ammonia since there's no water shortage.

5 0

3 years ago