A board of wood has a density of 0.487 g/cm3. The board is measured to have a length of 3.21 cm, a width of 12.2 cm and a height of 0.80 mm. What is the mass of the board?

The mass of board is 1.52 g.

Explanation:

Given data:

Density of wood = 0.487 g/cm³

Length of board = 3.21 cm

Width of board = 12.2 cm

Height of board = 0.80 mm (0.80/10=0.08 cm)

Mass of board = ?

Solution:

We know that density of an object is equal to the mass of substance divided by its volume. So we can calculate the mass from density formula.

Formula:

D = m/v

d = density

m = mass

v = volume

Now we will calculate the volume first.

V = length × width × height

V = 3.21 cm × 12.2 cm × 0.08 cm

V = 3.13cm³

Now we will calculate the mass.

D = m/v

0.487 g/cm³ = m/ 3.13 cm³

m = 0.487 g/cm³ × 3.13 cm³

m = 1.52 g

The mass of board is 1.52 g.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

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