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2 years ago

The runners have just started a race. They started at rest and are getting faster.

Chemistry

1 answer:

Anon25 [30]2 years ago

7 0

A. Acceleration is positive and speed is increasing.

<h3>Further explanation</h3>

The motion performed by a runner is part of a uniformly accelerated motion with constant acceleration.

Equation used

$\tt \boxed{\bold{v_f=v_i+at}}$

vf = final velocity

vi = vo = initial velocity

When a runner moves from rest, his speed will increase from being at rest (vi=0) and then move with a constant acceleration(a), and as soon as he crosses the finish line his acceleration will decrease (experience a deceleration ⇒a=- ) and decrease his speed until it finally stops

Velocity and speed are different because velocity itself is a vector quantity that takes into account direction and displacement, while speed is a scalar quantity (only distance).

So the speed does not take positive or negative values because it involves direction, while acceleration takes positive and negative values (deceleration) because it takes direction.

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The solubility of two slightly soluble salts of M^2+ , MA and MZ_2, are the same, 4 x 10^â4 mol/L.

LekaFEV [45]

Answer:

a) MZ₂

b) They have the same concentration

c) 4x10⁻⁴ mol/L

Explanation:

a) The solubility (S) is the concentration of the salt that will be dissociated and form the ions in the solution, the solubility product constant (Kps) is the multiplication of the concentration of the ions elevated at their coefficients. The concentration of the ions depends on the stoichiometry and will be equivalent to S.

The salts solubilization reactions and their Kps values are:

MA(s) ⇄ M⁺²(aq) + A⁻²(aq) Kps = S*S = S²

MZ₂(aq) ⇄ M⁺²(aq) + 2Z⁻(aq) Kps = S*S² = S³

Thus, the Kps of MZ₂ has a larger value.

b) A saturated solution is a solution that has the maximum amount of salt dissolved, so, the concentration dissolved is solubility. As we can notice from the reactions, the concentration of M⁺² is the same for both salts.

c) The equilibrium will be not modified because the salts have the same solubility. So, let's suppose that the volume of each one is 1 L, so the number of moles of the cation in each one is 4x10⁻⁴ mol. The total number of moles is 8x10⁻⁴ mol, and the concentration is:

8x10⁻⁴ mol/2 L = 4x10⁻⁴ mol/L.

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3 years ago

How do you predict the geometrical shape of NH3 on VSEPR model

Sauron [17]

Answer:

NH3 Ammonia

Explanation:

Ammonia has 4 regions of electron density around the central nitrogen atom (3 bonds and one lone pair). These are arranged in a tetrahedral shape. The resulting molecular shape is trigonal pyramidal with H-N-H angles of 106.7°.

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3 years ago

Which is a way that biotechnology has Not helped society? Bacteria is used to grow vaccines in large quantities. Drugs can be de

fenix001 [56]

Well, you just have to look for the one that does not have any positive/benefit.

1. is not the answer, since vaccines prevent countless people from disease and death.

2. is not the answer since animal abuse is not okay and the statement shows that science has become more efficient, therefore helping society become more efficient

3. is definitely not a positive effect that biotech has had on society. antibiotic-resistant bacteria endangers everyone. Therefore, this is the answer :)

4. is not the answer because helping people with diabetes be able to afford their medication is very helpful.

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3 years ago

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After moving down a group in the periodic table, the number of valence electrons

Delvig [45]

the number of Valence electrons remains the same

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2 years ago

Why do electrons flow through a wire?

I am Lyosha [343]

Answer:

When electrons flow through a conductor such as a wire, it is called, "Electricity".