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4 years ago

Which one of the following is a balanced equation?

Physics

1 answer:

yarga [219]4 years ago

5 0

D. 2Na (s) + MgF2 → 2NaF (s) + Mg (s)

Explanation:

From the given choices, 2Na (s) + MgF2 → 2NaF (s) + Mg (s) is balanced

A balanced equation is one that obeys the law of conservation of matter which states that "matter is neither created nor destroyed but transformed from one form to another".

We expect to find the same name of atoms on both sides of the equation.

let us examine the choices;

Zn (s) + HCl (g) → ZnCl2 (s) + H2 (g)

Reactants Products

Zn 1 1

H 1 2

Cl 1 2

Na (s) + O2 (g) → Na2O

Reactants products

Na 1 2

O 2 1

Na (s) + MgF2 → 2NaF (s) + Mg (s)

Reactants products

Na 1 2

Mg 1 1

F 2 2

2Na (s) + MgF2 → 2NaF (s) + Mg (s)

Reactants products

Na 2 2

Mg 1 1

F 2 2

learn more:

Balanced equation brainly.com/question/2947744

#learnwithBrainly

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Sphere A has an excess of 10 ^ 15 electrons and sphere B has an excess of 10 ^ 13 protons. They are separated by 2.0 m. What is

klasskru [66]

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3 years ago

Why is the formation of hydrogen bonds between water molecules categorized as cohesion

marishachu [46]

Answer: Because of the polarity of water molecules

Molecular <u>cohesion</u> is the attraction that molecules have for others of their same type. Depending on the intensity of this attraction, a substance is in a solid, liquid or gaseous state.

In this sense, water ( $H_{2}O$ ) can stick to itself through hydrogen bonds, because a water molecule consists of 2 hydrogen atoms attached to 1 oxygen atom.

The oxygen atom tends to monopolize more electrons and keeps them away from hydrogen. Then, it can be said that a water molecule will have a negative side (oxygen) and a positive side (hydrogen).

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3 years ago

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Misha Larkins [42]

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3 years ago

Resistors 1 and 2− R1 = 50 Ω , R2 = 90 Ω − are connected in series to a 6.0-V battery. Part APart complete What is the potential

kondor19780726 [428]

Answer:

Part A: The voltage across resistor R1 is approximately $\rm 2.1 \; V$ .

Part B: When the value of resistor R1 decreases, the current in this circuit will increase.

Part C: When the value of resistor R1 decreases, the voltage across resistor R1 will decrease.

Explanation:

Resistor R1 and and R2 are connected in series. That's equivalent to a single resistor of $R_1 + R_2 = 50 + 90 = 140\; \Omega$ . The voltage across the two resistor, combined, is equal to $\rm 6\; V$ . Hence by Ohm's Law, the current through the circuit will be equal to $\rm \dfrac{6\; V}{140\; \Omega} = \dfrac{3}{70}\; A$ .

These two resistors are connected in series. The voltage across each of them might differ. However, the current through each of them should both be equal to the current through the circuit. In this case, the current through both R1 and R2 should be equal to $\rm \dfrac{3}{70}\; A$ . Apply Ohm's Law (again) to find the voltage across R1:

$V = I \cdot R = \dfrac{3}{70} \times 50 \approx \rm 2.1\; V$ .

Since the equivalent resistance is equal to $R_1 + R_2$ , when the value of $R_1$ decreases, the equivalent resistance will also decrease. By Ohm's Law, $I = \dfrac{V}{R}$ . When the value of the denominator ( decreases, the value of the quotient, $I$ the current through the circuit, will increase.

Keep in mind that if two resistors are connected in series,

$I(R_1) = I(\text{Circuit}) = I(R_2)$ .

The resistance of R1 decreases, while the current through it increases. Applying Ohm's Law on R1 won't give much useful information. However, since the resistance of R2 stays the same, the voltage across it will increase when its current increases (again by Ohm's Law.)

Again, since the two resistors are connected in series,

$V(R_1) + V(R_2) = V(\text{Circuit}) = \rm 6 \; V$ ,

when the voltage across R2 increases, the voltage across R1 will decrease.

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3 years ago

How do you solve this ?<br> Why is the ans C not B ?

melomori [17]

Explanation:

Draw a free body diagram of the toolbox. There are two forces:

Weight force mg pulling down,

and applied force F pulling up.

Sum of forces in the y direction:

∑F = ma

F − mg = ma

45 N − 15 N = (3 kg) a

a = 10 m/s²

The answer should be B. It's possible the answer key has a mistake.

4 0

4 years ago