Given:
density of water is <span>approximately 1.0 g/mL
block of material
</span><span>volume of 1.2 x 10^4 in^3
and weighing 350 lb
</span>
Required:
Which will float
Solution:
D = M/V where D is density, M is mass and V is volume
convert <span>1.2 x 10^4 in^3 into mL
</span><span>1.2 x 10^4 in^3 (16.39 mL/ 1 in3) = 196,980 mL
</span>
convert <span>350 lb into grams
350 lb (454 grams/1 lb) = 158,900 grams
D = M/V = </span>158,900 grams/ <span>196,980 mL
D = 0.807 g/mL
The block will float in water because it is less dense than water</span>
If something is melting or boiling
Endothermic reactions mean heat is added
Answer:
[MgCl₂] = 1.05 m
Explanation:
Molality is a type of concentration that indicates the moles of solute in 1000g of solvent.
m = mol/kg.
Our solute is MgCl₂. We convert mass to moles:
25 g . 1mol / 95.21 g = 0.262 moles.
Our solvent is water → 250 mL of H₂O
We use density to determine the mass: density = m / V
Density . V = m → 0.9975 g/mL . 250 mL = 249.3 g
We convert from g to kg = 249.3 g . 1kg/1000g = 0.2493kg
molality → 0.262 mol /0.2493kg = 1.05
3. Atoms change into other atoms in chemical reactions.
The idea that you can transform one element into another was called alchemy, and was proven untrue a long time ago.