Index fossils<span> can be </span>used<span> to help determine the relative age of </span>rock<span> layers. </span>Index fossils<span> are from species that only existed for a short time. </span>Index fossils<span> are found in</span>rock<span> layers. Trilobites and Graptolites are </span><span>index fossils.</span>
Answer:
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 : The concentration of nitrate ions is 0.450 m.
Solution : Given,
Molarity of 
= 0.225 m
The balanced ionic equation is,
From the reaction, we conclude that the 1 mole of produces 2 moles of 
ions. That means the concentration of nitrate ions is twice the value of .
then, 0.225 m of gives 2 × 0.225 of ions
Now the concentration of ions is equal to 0.450 m.
Answer:
Explanation:
IT'S FOR NOW, PLEASE DELIVER IT TODAY !!! I NEED HELP IT'S CHEMICAL WORK...
Need more context maybe put a picture or explain a little more
