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4 years ago

7

Which of the following is a chemical change

2 answers:

alina1380 [7]4 years ago

5 0

What are the options u can't say that and expect me to know wat u talkin bout

mel-nik [20]4 years ago

5 0

I'm guessing the answer choices are:

A. ice melting

B. ice being carved

C. water boiling

D. water breaking down into hydrogen and oxygen

The answer, if any of these choices, would be C

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Which of the given will facilitate a normal Diels–Alder reaction?

babymother [125]

Answer:

D

Explanation:

- The rate of the Diels-Alder is orders of magnitude faster if there is an electron-withdrawing group on the dienophile. For example, replacing a hydrogen on ethene with the electron-withdrawing group CN results in about a 10^5 increase in the reaction rate.

- Other common electron withdrawing functional groups that will accelerate the Diels Alder reaction of dienophiles include aldehydes, ketones, and esters.

- In short, any functional group conjugated with the pi bond which can act as a pi acceptor will accelerate a Diels-Alder reaction with a typical diene.

- See attachment for graphical explanation.

7 0

3 years ago

Two cars start a race with initial velocity 7ms-1 and 4ms-1 respectively.Their acceleration are 0.4ms-2 and 0.5ms-2 respectively

Ronch [10]

The distance of the track is 600 m

Explanation:

The two cars move by uniformly accelerated motion, so we the distance they cover after a time t is described by the following suvat equation

$d=ut+\frac{1}{2}at^2$

where

u is the initial velocity

a is the acceleration

For car 1, we have

$d_1 = u_1 t + \frac{1}{2}a_1 t^2$

where

$u_1 = 7 m/s$ is the initial velocity of car 1

$a_1 = 0.4 m/s^2$ is the acceleration of car 1

So the equation can be rewritten as

$d_1 = 7t + 0.2t^2$

For car 2, we have

$d_2 = u_2 t + \frac{1}{2}a_2 t^2$

where

$u_2 = 4 m/s$ is the initial velocity of car 2

$a_2 = 0.5 m/s^2$ is the acceleration of car 2

So the equation can be rewritten as

$d_2= 5t + 0.25t^2$

The two cars finish the race at the same time: this means that they cover the same distance in the same time t, so we can write

$d_1 = d_2\\7t + 0.2t^2=5t + 0.25t^2$

And solving for t, we find

$2t - 0.05t^2= 0\\t(2-0.05t)=0$

Which gives two solutions:

t = 0 (initial instant)

t = 40 s

Therefore, the distance of the track is

$d_1 = 7t +0.2t^2 = 7\cdot 40+0.2\cdot 40^2=600 m$

Learn more about accelerated motion:

brainly.com/question/9527152

brainly.com/question/11181826

brainly.com/question/2506873

brainly.com/question/2562700

#LearnwithBrainly

7 0

4 years ago

2N2 Hy 03 2N₂²_0₂ +42 H₂O

Sholpan [36]

Yfytctucctiycbjj itvbyobiouvuviybhv

4 0

3 years ago

If the ultimate shear strength of steel is taken to be 3.00 109 Pa, what force is required to punch through a steel plate 1.60 c

photoshop1234 [79]

Answer:

Explanation:

Given

Ultimate shear strength $\tau =3\times 10^9\ Pa$

thickness of steel Plate $t=1.60\ cm$

Cross-sectional $A=1.20\times 10^2\ cm^2$

suppose d is the diameter of cross-section

$\frac{\pi }{4}d^2=1.20\times 10^2$

$d=12.359\ cm$

Shear area of circular cross-section

$A_s=\pi dt$

$A_s=\pi \times 12.359\times 1.6$

$A_s=62.13\ cm^2$

Shear Force $F_s=A_s\times \tau$

$F_s=62.13\times 10^2\times 3000$

$F_s=18.639\ MN$

6 0

3 years ago

Find the weight of a 60 kg astronaut on earth.<br> (Pls help)

ollegr [7]

Answer:

IT is 120 kg

Explanation:

7 0

3 years ago