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3 years ago

In order for matter or energy to be conserved, one must have a ____ system.

Chemistry

2 answers:

Oliga [24]3 years ago

7 0

Answer:

B. closed

Explanation:

In an open system both matter and energy is exchanged with the surroundings. Thus option A is incorrect.

In a closed system, matter is not transferred but energy is exchanged. Option B is correct.

Isolated system does not allow the exchange of matter or energy.

Options C and D are incorrect as there are no systems in thermodynamics called unique and stationary.

Leya [2.2K]3 years ago

6 0

Closed system. If the system is not closed, matter or energy can escape from the system. an example of this is if you react magnesium and hydrochloric acid in a open system. The H₂ gas is going to escape making it look like some of the mass disappeared . in that same reaction some in an open system will also loose heat to the surrounding which will make it look like less heat was produced.

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The sum of the protons and neutrons in the nucleus of an atom is called the _____?

True [87]

The sun of the protons a D neutrons in the nucleus of an atom is called the ATOMIC MASS

4 0

3 years ago

What is the final pressure (expressed in atm) of a 3.05 L system initially at 724 mm Hg and 298 K, that is compressed to a final

maksim [4K]

Hey there!:

V1 = 3.05 L

V2 = 3.00 L

P1 = 724 mmHg

P2 = to be calculated

T1 = 298 K

T2 = 273 K

Therefore:

P1*V1 / T1 = P2*V2 / T2

P2 = ( P1*V1 / T1 ) * T2 / V2

P2 = 724 * 3.05 * 273 / 298 * 3.00

P2 = 602838.6 / 894

P2 = 674.31 mmHg

1 atm ----------- 760 mmHg

atm ------------- 674.31 mHg

= 674.31 * 1 / 760

= 0.887 atm

Hope this helps!

5 0

3 years ago

[Ca2+] within the endoplasmic reticulum (ER) is 10-3M. Cytosolic [Ca2+] is 10-7M. Lysosomes in mammalian cells have an internal

Pani-rosa [81]

Answer:

B. Ca2+ import into the ER because it has the steeper concentration gradient

Explanation:

ΔGt = RT㏑(C₂/C₁)

where ΔGt is the free energy change for transport; R = 8.315 J/mol; T = 298 K; C₂/C₁ is ratio of concentrations inside and outside each organelle.

For Ca²⁺ import

ΔGt = 8.315 J/mol * 298 K * ㏑(10⁻³/10⁻⁷)

ΔGt= 3.42 kJ/mol

For H⁺ import

ΔGt = 8.315 J/mol * 298 K * ㏑ (10⁻⁴/10⁻⁷)

ΔGt = 2.73 kJ/mol

From the above values, ΔGt is greater for Ca²⁺ import because it has a steeper concentration gradient

8 0

3 years ago

One of the reactions that occurs in a blast furnace, in which iron ore is converted to cast iron, is Fe2O3 + 3CO → 2Fe + 3CO2 Su

Tpy6a [65]

Answer : The percent purity of $Fe_2O_3$ in the original sample is 87.94 %

Explanation :

The given balanced chemical reaction is:

$Fe_2O3+3CO\rightarrow 2Fe+3CO_2$

First we have to calculate the mass of Fe.

$\text{Moles of }Fe=\frac{\text{Mass of }Fe}{\text{Molar mass of }Fe}$

Molar mass of Fe = 55.8 g/mole

$\text{Moles of }Fe=\frac{1.79\times 10^3kg}{55.8g/mole}=\frac{1.79\times 10^3\times 1000g}{55.8g/mole}=3.15\times 10^4mole$

Now we have to calculate the moles of $Fe_2O_3$

From the balanced chemical reaction we conclude that,

As, 2 moles of Fe produced from 1 mole of $Fe_2O_3$

So, $3.15\times 10^4mole$ of Fe produced from $\frac{3.15\times 10^4}{2}=15750$ mole of $Fe_2O_3$

Now we have to calculate the mass of $Fe_2O_3$

$\text{ Mass of }Fe_2O_3=\text{ Moles of }Fe_2O_3\times \text{ Molar mass of }Fe_2O_3$

Molar mass of $Fe_2O_3$ = 159.69 g/mole

$\text{ Mass of }Fe_2O_3=(15750moles)\times (159.69g/mole)=2.515\times 10^6g=2.515\times 10^3kg$

Now we have to calculate the percent purity of $Fe_2O_3$ in the original sample.

Mass of original sample = $2.86\times 10^3kg$

$\text{Percent purity}=\frac{\text{Mass of }Fe_2O_3}{\text{Mass of sample}}\times 100$

$\text{Percent purity}=\frac{2.515\times 10^3kg}{2.86\times 10^3kg}\times 100=87.94\%$

Therefore, the percent purity of $Fe_2O_3$ in the original sample is 87.94 %

3 0

2 years ago

Explain what makes one mineral so precious or costly compared to another.

ValentinkaMS [17]

There are multiple factors that contribute to the cost of a mineral. First of all is the demand or application, which will be related to its physical properties. For example, nontarnishing metals like gold are held in high value for their appearance. Second is the supply of the mineral, those that only have a small quantity in the earth's crust are likely to be more expensive. Third is the cost of extraction and manufacturing. Some minerals may be abundantly found, but may be distributed over a wide area, meaning that it is still expensive to mine and transport.

8 0

3 years ago