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3 years ago

9

The statement "matter can be neither created nor destroyed by chemical means, but it can be changed from one form to another" is

the chemical law of
CONSERVATION OF MATTER

1 answer:

Assoli18 [71]3 years ago

4 0

I think false because matter cant be changed into something it isnt.<span />

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A sample of nitrogen gas is collected over water at a temperature of 23.0 C. What is the pressure of the nitrogen gas if atmosph

Whitepunk [10]

We first consider the gases that will be present in that sample.
First, there will be nitrogen, as stated. Second, there will also be water in the form of water vapor. For this, we need the vapor pressure of water at 23.0 °C, which is about 21.0 mmHg. Now, the sum of the vapor pressures of the gases will be equivalent to the total pressure. So the pressure of nitrogen gas is:
785 - 21
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Sulfur hexafluoride, SF6, is a colorless, odorless, very unreactive gas. Calculate the pressure (in atm) exerted by 2.02 moles o

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Answer:

9.15 atm

Explanation:

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Consider the reaction. 2 Pb ( s ) + O 2 ( g ) ⟶ 2 PbO ( s ) An excess of oxygen reacts with 451.4 g of lead, forming 367.5 g of

Art [367]

Answer : The percent yield of the reaction is, 75.6 %

Solution : Given,

Mass of Pb = 451.4 g

Molar mass of Pb = 207 g/mole

Molar mass of PbO = 223 g/mole

First we have to calculate the moles of Pb.

$\text{ Moles of }Pb=\frac{\text{ Mass of }Pb}{\text{ Molar mass of }Pb}=\frac{451.4g}{207g/mole}=2.18moles$

Now we have to calculate the moles of $PbO$

The balanced chemical reaction is,

$2Pb(s)+O_2(g)\rightarrow 2PbO(s)$

From the reaction, we conclude that

As, 2 mole of $Pb$ react to give 2 mole of $PbO$

So, 2.18 mole of $Pb$ react to give 2.18 mole of $PbO$

Now we have to calculate the mass of $PbO$

$\text{ Mass of }PbO=\text{ Moles of }PbO\times \text{ Molar mass of }PbO$

$\text{ Mass of }PbO=(2.18moles)\times (223g/mole)=486.1g$

Theoretical yield of $PbO$ = 486.1 g

Experimental yield of $PbO$ = 367.5 g

Now we have to calculate the percent yield of the reaction.

$\% \text{ yield of the reaction}=\frac{\text{ Experimental yield of }PbO}{\text{ Theoretical yield of }PbO}\times 100$

$\% \text{ yield of the reaction}=\frac{367.5g}{486.1g}\times 100=75.6\%$

Therefore, the percent yield of the reaction is, 75.6 %

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3 years ago

When are the products of an equilibrium reaction favored? When the reaction is endothermic. When the equilibrium constant is lar

PtichkaEL [24]

Product are favored at ...

example 2A + 3B = 5C + D if reaction is exothermic ....delta H = NEGATIVE)

A decrease in temperature favors the forward reaction (more product formed)
as heat is considered as a product

For the exam I have given: A decrease in pressure (volume increases as pressure decreases) .... there are more number of moles on the product side (6 in all) .....so according to LCP decreasing pressure will revert back to increase pressure and to do that equilibrium position shifts to the right (product)

decreasing concentration of product will cause a disturbance in equilibrium position....and reaction will restore its equilibrium by shifting to the right

(I believe its like this)

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3 years ago

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