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3 years ago

Min is asked to balance the equation below.

2 answers:

6 0

It is incorrect, because the identity of the original product has changed. Ca3(OH)2 does not exist! It is no longer calcium hydroxide. To balance an equation, you must manipulate the coefficients, a.k.a. the big numbers that go before reactants or products. Subscripts, the little numbers inside the reactants or products, cannot be changed without completely changing the substance.

Wewaii [24]3 years ago

6 0

Ca3P2 + H2O → Ca(OH)2 + PH3

Min’s result: Ca3P2 + H2O → Ca3(OH)2 + PH3

Which best describes Min’s method for balancing the chemical equation?

It is correct, because now there are three Ca atoms on each side of the equation.

It is incorrect, because the identity of the original product has changed.

It is correct, because Ca3(OH)2 creates a more stable compound.

It is incorrect, because the subscript “2” should be added instead.

Answer: B

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A pure substance can be a ..................... (a) element (b) compound (c) either element or compound (d)none of these

stiks02 [169]

Answer:

Explanation:

An element is a pure substance that can not be broken down into anything simpler

A compound in also a pure substance held together in fixed proportion through chemical bonds

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3 years ago

Read 2 more answers

An instrument is thrown upward with a speed of 15 m/s on the surface of planet X where the acceleration due to gravity is 2.5 m/

Katen [24]

<h2>Answer: 12 s</h2>

Explanation:

The situation described here is parabolic movement. However, as we are told <u>the instrument is thrown upward</u> from the surface, we will only use the equations related to the Y axis.

In this sense, the main movement equation in the Y axis is:

$y-y_{o}=V_{o}.t-\frac{1}{2}g.t^{2}$ (1)

Where:

$y$ is the instrument's final position

$y_{o}=0$ is the instrument's initial position

$V_{o}=15m/s$ is the instrument's initial velocity

$t$ is the time the parabolic movement lasts

$g=2.5\frac{m}{s^{2}}$ is the acceleration due to gravity at the surface of planet X.

As we know $y_{o}=0$ and $y=0$ when the object hits the ground, equation (1) is rewritten as:

$0=V_{o}.t-\frac{1}{2}g.t^{2}$ (2)

Finding $t$ :

$0=t(V_{o}-\frac{1}{2}g.t^{2})$ (3)

$t=\frac{2V_{o}}{g}$ (4)

$t=\frac{2(15m/s)}{2.5\frac{m}{s^{2}}}$ (5)

Finally:

$t=12s$

3 0

3 years ago

When matter transitions between solid liquid and gas

iVinArrow [24]

Its called the Phase Transition. Im assuming your asking what is it called when matter transitions between solid liquid and gas.

5 0

3 years ago

How do I calculate speed, velocity, and acceleration? I need the formulas too

vodomira [7]

Speed is the secular unit, which means it only measures "how fast it goes."
$speed= \frac{distance}{time}$
Velocity is a victory unit, which means it measures "both how fast it goes AND the direction."
$velocity= displacement/time$
Acceleration is the change of velocity over time.
$acceleration = \frac{change in velocity}{time}$

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3 years ago

A punter wants to kick a football so that the football has a total flight time of 4.70s and lands 56.0m away (measured along the

Sindrei [870]

Answer:

Explanation:

How long does the football need to rise?

4.70/3 = 2.35 s

What height will the football reach?

h = ½(9.81)2.35² = 27.1 m

With what speed does the punter need to kick the football?

vy = g•t = 9.81(2.35) = 23.1 m/s

vx = d/t = 56.0/4.70 = 11.9 m/s

v = √(vx²+vy²) = 26.0 m/s

At what angle (θ), with the horizontal, does the punter need to kick the football?

θ = arctan(vy/vx) = 62.7°

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2 years ago