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3 years ago

Discuss how to separate a mixture of iron fillings, salt, sand, and wood chips.

1 answer:

3 0

<span>Wrap a magnet in plastic lunch wrap and move it through the mixture of the three solids. The iron filings will stick to the magnet. The filings can be removed by unwrapping the plastic from the magnet carefully! Mix the remaining salt and sand in water and stir.</span>

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Which mechanisms is most significant in returning the ion concentrations to the resting state?

IceJOKER [234]

Answer:

Active transport by the Na+-K+ pump

Explanation:

Active transport by the Na+-K+ pump

Maintenance (and restoration) of the resting ion concentrations depends on the Na+-K+ pump. Once gated ion channels are closed, the combined action of the pump and ion leakage (particularly that of K+) establishes a resting membrane potential in a typical neuron of around âˆ'70 mV.

5 0

3 years ago

Which law is associated with inertia

Doss [256]

Newton's first law is the answer.

5 0

3 years ago

What is the acceleration of the object’s motion? 0.5 m/s2 -0.5 m/s2 2 m/s2 -2 m/s2

djverab [1.8K]

Answer: -2m/s2

Explanation:

Using the following equation ; acceleration = Change in velocity / time

i.e a = v - u / t

where 'a' = acceleration

v = final velocity

u = initial velocity

t = time

Therefore; from the graph we have acceleration to be, 0 - 6m/s / 3s = -2m/s2

5 0

3 years ago

A buffer solution is made that is 0.347 M in H2C2O4 and 0.347 M KHC2O4.

irga5000 [103]

Answer:

1. pH = 1.23.

2. $H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)$

Explanation:

Hello!

1. In this case, for the ionization of H2C2O4, we can write:

$H_2C_2O_4\rightleftharpoons HC_2O_4^-+H^+$

It means, that if it is forming a buffer solution with its conjugate base in the form of KHC2O4, we can compute the pH based on the Henderson-Hasselbach equation:

$pH=pKa+log(\frac{[base]}{[acid]} )$

Whereas the pKa is:

$pKa=-log(Ka)=-log(5.90x10^{-2})=1.23$

The concentration of the base is 0.347 M and the concentration of the acid is 0.347 M as well, as seen on the statement; thus, the pH is:

$pH=1.23+log(\frac{0.347M}{0.347M} )\\\\pH=1.23+0\\\\pH=1.23$

2. Now, since the addition of KOH directly consumes 0.070 moles of acid, we can compute the remaining moles as follows:

$n_{acid}=0.347mol/L*1.00L=0.347mol\\\\n_{acid}^{remaining}=0.347mol-0.070mol=0.277mol$

It means that the acid remains in excess yet more base is yielded due to the effect of the OH ions provided by the KOH; therefore, the undergone chemical reaction is:

$H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)$

Which is also shown in net ionic notation.

Best regards!

4 0

3 years ago

What is neutron number for calcium

notka56 [123]

Answer:

20 neutrons

Explanation:

(not really any just look at a periodic table)

5 0

3 years ago