I think the correct answer would be <span>charged and insulated wire wrapped around a piece of iron. The charge in the wire would make magnetic fields through the aid of the magnetic properties of iron. Hope this helps. Have a nice day.</span>
You are looking for an element in the fourth period and a transition metal. As most have about 3 valence electrons. Gallium and Scandium work perfectly.
When the use of significant figures and rounding up is applied correctly the mass of the mixture will be 80.5 g.
In cases of addition or subtraction, only the last significant figure of every number is taken into account.
In 30.05, this is 5, in the hundredths. When we look at 50.0, the last significant figure is 0, and it is in the tenths. And in 0.4006, the last significant figure is 6, in the ten thousandths. Of these three, the 0 from 50.0 is in the leftmost position, which means that the last significant figure of the result needs to be in the same position (in the tenths).
Moving onto the actual algebraic operation:
30.05 g + 50.0 g + 0.4006 = 80.4506 g
As we established, the last significant figure should be in the tenths, and we will have to round up 4 to 5 (trailing numbers are greater than 0), which means that the resulting mass will be 80.5 g.
You can learn more about significant figures here:
brainly.com/question/14804345
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It’s because thermosetting plastics a very dangerous for the atmosphere idk man srry
Answer:
Ka = ( About ) 5 x 10^ - 8
Explanation:
Let us first identify the dissociation equation for this weak acid,
HA ⇌ ( H+ ) + A¯
Knowing this, we can tell what the equilibrium expression is, respectively,
Ka = ( [ H+ ] [ A¯ ] ) / [ HA ]
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Now let us use the given pH 3.99 to calculate [ H+ ], knowing that pH = −log [H+],
3.99 = - log[H+],
[H+] = 10 ^ - 3.99,
[H+] = ( About ) 1 * 10^-4 M
Substitute known values into the equilibrium expression,
Ka = [( 1 x 10^ - 4 ) ( 1 x 10^ ¯4 )] / 0.199,
Ka = ( About ) 5 x 10^ - 8
