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3 years ago

Pls helpits rlly hard

Chemistry

1 answer:

victus00 [196]3 years ago

5 0

Answer:

5: 0.16

6: 50

Explanation:

Question 5:

We can use the equation density = mass/ volume.

We already have the mass (12g), but now we need to find the volume of the cylinder.

The equation for this is πr²h

So we know the radius is 2 and the height is 6.

π x (2)² x 6 = 24π = 75.398cm³

Now we can use the density equation above:

12/75.398 = 0.1592g/cm³ = 0.16g/cm³.

Question 6:

This time, we have to rearrange the equation density = mass/ volume to find the mass.

We know mass = density x volume.

From the question, the density is 2.5g/mL and the volume is 20mL.

Following the equation above, we do 2.5 x 20 to get 50g.

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Buck's Turf Care Company mowed 233 lawns over a 11 week period. What is the average weekly rate of mowing lawns?

masya89 [10]

Answer: 21 lawns per week

Explanation:

The average weekly rate refers to how many lawns were mowed per week given that 233 were done in 11 weeks.

Rate will be given by;

= Lawns mowed / Weeks taken

= 233 / 11

= 21 lawns per week

6 0

3 years ago

What is the density of an object that has a mass of 6.5 g and when placed in water displaces the volume from 4.5mL to 11.8mL? ro

KengaRu [80]

Answer:

$\rho =0.9g/mL$

Explanation:

Hello,

In this case, due to the volume displacement caused the by the object's submersion, it's volume is:

$V=11.8mL-4.5mL=7.3 mL$

In such a way, considering the mathematical definition of density, it turns out:

$\rho =\frac{m}{V}=\frac{6.5g}{7.3mL}\\ \\\rho =0.89g/mL$

Rounding to the nearest tenth we finally obtain:

$\rho =0.9g/mL$

Regards.

3 0

3 years ago

Explain why calcium (Ca) has a greater atomic radius than magnesium (Mg).

g100num [7]

Answer:

Magnesium nucleus will attract the electrons more toward it and therefore, shrinking the size of the atom. Magnesium atom is smaller than Calcium atom because Calcium has more electron ( 20e− ) which will occupy more energy levels ( n=4 for Calcium versus n=3 for Magnesium)

8 0

3 years ago

What is the name for SO2

Tanzania [10]

Sulphur Dioxide. Toxic. Don't eat it.

7 0

4 years ago

The dissociation of sulfurous acid (H2SO3) in aqueous solution occurs as follows:

aksik [14]

Answer:

The [SO₃²⁻]

Explanation:

From the first dissociation of sulfurous acid we have:

H₂SO₃(aq) ⇄ H⁺(aq) + HSO₃⁻(aq)

At equilibrium: 0.50M - x x x

The equilibrium constant (Ka₁) is:

$K_{a1} = \frac{[H^{+}] [HSO_{3}^{-}]}{[H_{2}SO_{3}]} = \frac{x\cdot x}{0.5 - x} = \frac {x^{2}}{0.5 -x}$

With Ka₁= 1.5x10⁻² and solving the quadratic equation, we get the following HSO₃⁻ and H⁺ concentrations:

$[HSO_{3}^{-}] = [H^{+}] = 7.94 \cdot 10^{-2}M$

Similarly, from the second dissociation of sulfurous acid we have:

HSO₃⁻(aq) ⇄ H⁺(aq) + SO₃²⁻(aq)

At equilibrium: 7.94x10⁻²M - x x x

The equilibrium constant (Ka₂) is:

$K_{a2} = \frac{[H^{+}] [SO_{3}^{2-}]}{[HSO_{3}^{-}]} = \frac{x^{2}}{7.94 \cdot 10^{-2} - x}$

Using Ka₂= 6.3x10⁻⁸ and solving the quadratic equation, we get the following SO₃⁻ and H⁺ concentrations:

$[SO_{3}^{2-}] = [H^{+}] = 7.07 \cdot 10^{-5}M$

Therefore, the final concentrations are:

[H₂SO₃] = 0.5M - 7.94x10⁻²M = 0.42M

[HSO₃⁻] = 7.94x10⁻²M - 7.07x10⁻⁵M = 7.93x10⁻²M

[SO₃²⁻] = 7.07x10⁻⁵M

[H⁺] = 7.94x10⁻²M + 7.07x10⁻⁵M = 7.95x10⁻²M

So, the lowest concentration at equilibrium is [SO₃²⁻] = 7.07x10⁻⁵M.

I hope it helps you!

8 0

3 years ago