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user100 [1]
3 years ago
5

. What is the mass, in grams, of a sample of 7.83 × 1024 atoms of helium (He)?

Chemistry
1 answer:
erica [24]3 years ago
6 0
Moles He = 7.83 x 10^24 / 6.02 x 10^23 =13.0 

<span>mass He = 13.0 mol x 4.00 g/mol = 52.0 g</span>
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Perform unit conversions and determine Re for the case when a fluid with density of 92.8 lbm/ft3 and viscosity of 4.1 cP (centip
erastovalidia [21]

Answer:

Re=309926.13

Explanation:

density=92.8lbm/ft3*(0.45kg/1lbm)*(1ft3/0.028m3)=1491.43kg/m3

viscosity=4.1cP*((1*10-3kg/m*s)/1cP)=0.0041kg/m*s

velocity=237ft/min*(1min/60s)*(0.3048m/1ft)=1.2m/s

diameter=28inch*(0.0254m/1inch)=0.71m

Re=(density*velocity*diameter)/viscosity=(1491.43kg/m3*1.2m/s*0.71m)/0.0041kg/m*s

Re=309926.13

4 0
3 years ago
⚠️HELP DUE IN 10 MINS WILL GIVE BRAINLIEST!!! THANKS⚠️
LenKa [72]

Answer:

hahahh noob

Explanation:

3 0
3 years ago
In a coffee cup calorimeter, 1.60 g of NH4NO3 is mixed with 75.0 g of water at an initial temperature of 25.00 degrees C. After
igomit [66]

Answer:

+26.6kJ/mol

Explanation:

The enthalpy of dissolution of NH₄NO₃ is:

NH₄NO₃(aq) + ΔH  → NH₄⁺ + NO₃⁻

Where ΔH is the heat of reaction that is absorbed per mole of NH₄NO₃,

The moles that reacts in 1.60g are (Molar mass NH₄NO₃:80g/mol):

1.60g * * (1mol / 80g) = 0.02 moles reacts

To find the heat released in the coffee cup calorimeter, we must use the equation:

Q = m×ΔT×C

Where Q is heat released,

m is mass of the solution

ΔT is change in temperature (Final temperature - Initial temperature)

C is specific heat of the solution (4.18J/g°C)

Mass of the solution is:

1.60g + 75g = 76.60g

Change in temperature is:

25.00°C - 23.34°C = 1.66°C

Replacing:

Q = m×ΔT×C

Q = 76.60g×1.66°C×4.18J/g°C

Q = 531.5J

This is the heat released per 0.02mol. The heat released per mole (Enthalpy change for the dissolution of NH₄NO₃) is:

531.5J / 0.02mol = 26576J/ mol =

+26.6kJ/mol

<em>+ because the heat is absorbed, the reaction is endothermic-</em>

7 0
3 years ago
What is the percentage by mass of nitrogen in the fertiliser (NH4)3PO4? [Ar: H = 1, N = 14, O = 16, P = 31]
BaLLatris [955]

Answer:

(NH4)3PO4 is 28.2 % N , 8.1% H, 20.8 % P and 43.0 % O by mass.

Explanation:

the formula In chemistry, the mass fraction of a substance within a mixture is the ratio w_{i} of the mass m_{i} of that substance to the total mass {\displaystyle m_{\text{tot}}} of the mixture. Expressed as a formula, the mass fraction is: {\displaystyle w_{i}={\frac {m_{i}}{m_{\text{tot}}}}.}

6 0
3 years ago
Which property of metals allows aluminum to be flattened into thin sheets of aluminum foil?
Gnoma [55]

Answer:

malleability

Explanation:

3 0
3 years ago
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