156 g sample of steel has a volume of 20.0 mL. What is the density of the steel sample? a g/cm3 Your answer should be rounded to

Answer:

1.2×10²³ atoms.

Explanation:

In the problem, we see the data:

Mole of propanone = 0.20 mole

Calculating the number of atoms in propanone =?

According to Avogadro's principle, one mole of a substance contains 6.022×10²³ atoms.

This means that one mole of propanone also holds 6.022×10²³ atoms.

Thus, we can determine the atom count in 0.20 mole of propanone as:

1 mole of propanone contains 6.022×10²³ atoms.

Accordingly, 0.20 mole of propanone will have = 0.2 × 6.022×10²³ = 1.2×10²³ atoms.

Therefore, 0.20 mole of propanone contains

1.2×10²³ atoms.

The amount of heat needed to elevate an object's temperature can be determined using the formula,
heat = mass x specific heat x (T2 - T1)
Thus, specific heat can be found with the following formula,
specific heat = heat / (mass x (T2 - T1))
By substituting,
specific heat = 645 J / ((28.4 g)(15.5 - - 11.6))
The calculated specific heat from the above equation is 0.838 J/g°C. 

Answer:

inspect the packaging

Explanation:

M = 81.50g, mm = m/n
n =???
PV = nRT --> n = PV/RT
n = (1.75)(4.92)/(.0821)(307)
n = 8.61/25.20 =.342
--> mm = m/n = 81.5/.342 = 238.58