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3 years ago

6

Calculate the density of helium if a balloon with a capacity of 5.00 L holds 0.890 g.

1 answer:

liubo4ka [24]3 years ago

5 0

Answer:

Explanation:

Density is m/V. Also, 1 liter = 1000 $cm^3$ . So, we get 0.890/(5*1000) = $1.78*10^{-4}$ g/cm^3. You can convert this to kg/m^3 as well by multiplying it by 10. Depends which one you want.

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You are balancing an ionic compound. Let's call it: AB.

rewona [7]

Answer:- $A_3B_2$

Explanations:- It is given that the charge for A is +2 and the charge for B is -3. The over all compound is neutral means the over all charge is zero. For making the over all charge zero, we need 3 positive ions and 2 negative ions. This makes a +6 charge for A and -6 charge for B and the over all charge is zero.

Also, if we think about the criss cross then charge of A becomes the subscript of B and the charge of B becomes the subscript of A.

So, the formula of the ionic compound is $A_3B_2$ . In this compound the ratio of A to B is 3:2.

The balanced equation could be shown as:

$3A+2B\rightarrow A_3B_2$

8 0

2 years ago

how many calories of energy are given off to lower the temperature of 100.0g of iron from 150.0°C to 35.0°C?

jeyben [28]

Answer:

ΔT = Tfinal − Tinitial = 150°C − 35.0°C = 125°C

given the specific heat of iron as 0.108 cal/g·°C

heat=(100.0 g)(0.108 cal /g· °C )(125°C) =

100x 0.108x125= 1350 cal

4 0

3 years ago

What I need help fast!

ozzi

The correct answer would be 3

3 0

2 years ago

Be sure to answer all parts. In the average adult male, the residual volume (RV) of the lungs, the volume of air remaining after

Alenkinab [10]

<u>Answer:</u>

<u>For a:</u> The number of moles of air present in the RV is 0.047 moles

<u>For b:</u> The number of molecules of gas is $2.83\times 10^{22}$

<u>Explanation:</u>

<u>For a:</u>

To calculate the number of moles, we use the equation given by ideal gas follows:

$PV=nRT$

where,

P = pressure of the air = 1.00 atm

V = Volume of the air = 1200 mL = 1.2 L (Conversion factor: 1 L = 1000 mL)

T = Temperature of the air = $37^oC=[37+273]K=310K$

R = Gas constant = $0.0821\text{ L. atm }mol^{-1}K^{-1}$

n = number of moles of air = ?

Putting values in above equation, we get:

$1.00atm\times 1.2L=n_{air}\times 0.0821\text{ L atm }mol^{-1}K^{-1}\times 310K\\n_{air}=\frac{1.00\times 1.2}{0.0821\times 310}=0.047mol$

Hence, the number of moles of air present in the RV is 0.047 moles

<u>For b:</u>

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of molecules.

So, 0.047 moles of air will contain $(0.047\times 6.022\times 10^{23})=2.83\times 10^{22}$ number of gas molecules.

Hence, the number of molecules of gas is $2.83\times 10^{22}$

7 0

2 years ago

What have all living things evolved from?

dedylja [7]

Earlier species thanks to evolution. hope this helped!

3 0

3 years ago

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