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3 years ago

Water enters a 4.00-m3 tank at a rate of 6.33 kg/s and is withdrawn at a rate of 3.25 kg/s. The tank is initially half full.

Chemistry

1 answer:

olga55 [171]3 years ago

8 0

Answer:

At the start of the process, the volume not occupied by the water is 2 m3

Explanation:

At the start of the process you have a half full tank. It means that also a half is empty (not occupied by water).

Since the volume is 4 m3, 2 m3 are full (occupied by water) and 2 m3 (not occupied by water).

The volume in time will be

$V(t)=V_0+(f_i-f_o)*t\\\\V(t) = 2 +(6.33/1000-3.25/1000)*t=2+0.00308*t \, \, [m3]$

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Answer:

Explanation:

The first election shell can only hold 2 electrons, but the next one can hold up to 8

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2 years ago

Read the chemical equation.

Sladkaya [172]

Answer:- D. 1.8 moles of Fe and $2.7molCO_2$ .

Solution:- The balanced equation is:

$Fe_2O_3+3CO\rightarrow 2Fe+3CO_2$

let's first figure out the limiting reactant using the given moles and mol ratio:

$1.8molFe_2O_3(\frac{3molCO}{1molFe_2O_3})$

= 5.4 mol CO

From calculations, 5.4 moles of CO are required to react completely with 1.8 moles of Iron(III)oxide but only 2.7 moles of CO are available. It means CO is limiting reactant.

Products moles depends on limiting reactant. Let's calculate the moles of each reactant formed for given 2.7 moles of CO.

$2.7molCO(\frac{2molFe}{3molCO})$

= 1.8 mol Fe

$2.7molCO(\frac{3molCO_2}{3molCO})$

= $2.7molCO_2$

So, the correct choice is D. 1.8 moles of Fe and $2.7molCO_2$ are formed.

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3 years ago

A mileage test is conducted for a new car model. Thirty randomly selected cars are driven for a month and the mileage is measure

Leni [432]

Answer: $(27.81,\ 29.39)$

Explanation:

Given : Sample size : n= 30 , it means it is a large sample (n≥ 30), so we use z-test .

Significance level : $\alpha: 1-0.95=0.05$

Critical value: $z_{\alpha/2}=1.96$

Sample mean : $\overline{x}=28.6$

Standard deviation : $\sigma=2.2$

The formula to find the confidence interval is given by :-

$\overline{x}\pm z_{\alpha/2}\dfrac{\sigma}{\sqrt{n}}$

i.e. $28.6\pm (1.96)\dfrac{2.2}{\sqrt{30}}$

i.e. $28.6\pm 0.787259889321$

$\approx28.6\pm 0.79=(28.6-0.79,28.6+0.79)=(27.81,\ 29.39)$

Hence, the 95% confidence interval for the mean mpg in the entire population of that car model = $(27.81,\ 29.39)$

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3 years ago

Calculate the molality of a solution formed by adding 6.30 g NH4CL to 15.7 g of water

babymother [125]

Answer:

Molality = 7.5 mol/kg

Explanation:

Given data:

Mass of NH₄Cl = 6.30 g

Mass of water = 15.7 g (15.7/1000 =0.016 kg)

Molality = ?

Solution:

Formula of molality:

Molality = Moles of solute / mass of solvent in gram

Now we will first calculate the number of moles of solute( NH₄Cl )

Number of moles = mass/ molar mass

Molar mass of NH₄Cl = 53.491 g/mol

Number of moles = 6.30 g/ 53.491 g/mol

Number of moles = 0.12 mol

Now we will calculate the molality.

Molality = Moles of solute / mass of solvent in gram

Molality = 0.12 mol / 0.016 kg

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or (m=mol/kg)

Molality = 7.5 mol/kg

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3 years ago

Which of the following is the best hypothesis?

DerKrebs [107]

Answer:

B.) If sodium carbonate is added to vinegar, the reaction will absorb heat.

Explanation:

A.) is incorrect because this is not testable. Rather, it is just an opinion that cannot be proven correct or incorrect.

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C.) is incorrect because this statement explains something that does not need to be tested. It is an example of a physical change when one tears a piece of paper.

D.) is incorrect because this is already a true statement. It is obvious that not all reactions absorb/release heat. While tests could be run to further prove this statement true, it is already considered accurate.

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2 years ago

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