Answer:
0.24 g/mL
Explanation:
The density of an object is given by the ratio between its mass and its volume:
where
m is the mass of the object
V is its density
In this problem, we have:
m = 7.0 g is the mass of the object
The volume of an irregular shaped object can be measured by putting it into water, and by measuring the difference in water volume.
In this case,
is the initial volume of water
is the final volume of water
So the volume of the object is
Therefore, the density of the object is:
Answer: 3.4 L
Explanation:
To calculate the moles, we use the equation:
The balanced chemical equation for reaction of Hydrogen chloride gas with oxygen to form water vapor and chlorine gas.
According to stoichiometry :
4 moles of 
produce = 2 moles of 
Thus 0.29 moles of will produce =
of
Volume of 
Thus 3.4 L of of water would be produced by this reaction if 6.5 L of hydrogen chloride were consumed
<span>An example of a homologous structure is the forelimb of a whale, a human, and a dog.
Homologous structures have the same structure, but may have a different function.
Homologous structures indicate a common ancestor.
A homologous structure is an organ or bone that's in common between different animals that demonstrates an anatomical commonality indicating that the animals share a common ancestor. This is in contrast to analogous structures where two unrelated animals have structures with similar forms or functions due to convergent evolution. With that in mind, let's look at the available options and see what fits.
An example of a homologous structure is the wing of a bird and an insect.
* This is an example of an analogous structure, so this is a bad choice.
An example of a homologous structure is the forelimb of a whale, a human, and a dog.
* Exactly. This is a good example of a homologous structure, so this is a good choice.
Homologous structures have the same function but a different structure.
* False. This is a type of analogous structure.
Homologous structures have the same structure, but may have a different function.
* True. A homologous structure is a structure that was present in a common ancestor of different animals. Further evolution may have caused those animals to diverge and the common structure may now be used for different purposes. So this is a good choice.
Homologous structures indicate a common ancestor.
* Yes, by definition.
Homologous structures do not indicate a common ancestor.
* Since the previous option was true, this must be false, so a bad choice.</span>
Answer:
0.804g of NaHCO₃ you must add
Explanation:
pKa of HCO₃⁻/CO₃²⁻ is 10.32.
It is possible to find pH of a buffer by using H-H equation, thus:
pH = pka + log [A⁻] / [HA]
<em>Where [HA] is concentration of acid (HCO₃⁻) and [A⁻] is concentration of conjugate acid (CO₃²⁻).</em>
Moles of CO₃²⁻ = K₂CO₃ are:
4.00g ₓ (1mol / 138.206g) = 0.0289 moles CO₃²⁻
Replacing:
10.80 = 10.32 + log [0.0289] / [HCO₃⁻]
[HCO₃⁻] = 0.009570 moles you need to add to obtain the desire pH
As molar mass of NaHCO₃ is 84.007g/mol, mass of NaHCO₃ is:
0.009570 moles ₓ (84.007g / mol) =
<h3>0.804g of NaHCO₃ you must add</h3>
Answer:
D.
Volcanic eruptions act as constructive forces when lava builds up to form volcanoes and plateaus.
Explanation:
Volcanic eruptions brings lava to the surface. They are powerful constructive forces that builds the earth and adds new materials to the surface.
- Molten rocks from within the earth reaches the surface.
- They then build up and accumulate to form very interesting land masses.
- A constructive force adds new materials to the earth.
- Weathering is a destructive force.
- One notable constructive force usually occurs along divergent margins.
- The mid-oceanic ridge is a very fascinating example
