Ask question

Ask question

All categories

3 years ago

9

Determine whether each of the following is exothermic or endothermic and indicate the sign of δh. A. Natural gas burning on a st

ove b. Isopropyl alcohol evaporating from skin c. Water condensing from steam

1 answer:

Oxana [17]3 years ago

5 0

Answer:

A) exothermic, δh is negative

B) endothermic, δh is positive

C) endothermic, δh is positive

Explanation:

And endothermic process absorbs heat from its sorrounding, cooling the sorrounding down. Whereas an exothermic process releases heat to its sorrounding raising the temperature of the sorrounding system.

You might be interested in

The near point of an eye is 110 cm. A corrective lens is to be used to allow this eye to focus clearly on objects 26.0 cm in fro

irga5000 [103]

Answer:

The focal length of the lens is 34.047 cm

The power of the needed corrective lens is 2.937 diopter.

Explanation:

Distance of the object from the lens,u = 26 cm

Distance of the image from the lens ,v= -110 cm

(Image is forming on the other side of the lens)

Since ,lens of the human eye is converging lens,convex lens.

Using a lens formula:

$\frac{1}{f}=\frac{1}{u}+\frac{1}{v}$

$\frac{1}{f}=\frac{1}{26 cm}+\frac{1}{-110 cm}$

f = 34.047 cm = 0.3404 m

Power of the lens = P

$P=\frac{1}{f}=\frac{1}{0.34047 m}=2.937 diopter$

6 0

3 years ago

What mistake did Dominic make?

Tatiana [17]

Answer:

Im not sure who you are talking about, but if you are talking about Dominic Raab, well, he failed to make a crucial phone call to seek urgent help airlifting translators out of Afghanistan. if you are not talking about this Dominic, then please add more information to your question.

7 0

2 years ago

A mass free to vibrate on a level, frictionless surface at the end of a horizontal spring is pulled 35 cm from its equilibrium p

saul85 [17]

Answer:

0.67 s

Explanation:

This is a simple harmonic motion (SHM).

The displacement, $x$ , of an SHM is given by

$x = A\cos(\omega t)$

A is the amplitude and $\omega$ is the angular frequency.

We could use a sine function, in which case we will include a phase angle, to indicate that the oscillation began from a non-equilibrium point. We are using the cosine function for this particular case because the oscillation began from an extreme end, which is one-quarter of a single oscillation, when measured from the equilibrium point. One-quarter of an oscillation corresponds to a phase angle of 90° or $\frac{\pi}{4}$ radian.

From trigonometry, $\sin A =\cos B$ if A and B are complementary.

At $t = 0$ , $x = 3.5$

$3.5 = A\cos(\omega \times0)$

$A =3.5$

So

$x = 3.5\cos(\omega t)$

At $t = 0.12$ , $x = 1.5$

$1.5 = 3.5\cos(0.12\omega)$

$\cos(0.12\omega)=\dfrac{1.5}{3.5}=0.4286$

$0.12\omega =\cos^{-1}0.4286$

$0.12\omega = 1.13$

$\omega = 9.4$

The period, $T$ , is related to $\omega$ by

$T = \dfrac{2\pi}{\omega} = \dfrac{2\times3.14}{9.4}=0.67$

5 0

3 years ago

In a series circuit what effect will adding more resistors to the circuit have

zhuklara [117]

Answer:In a series circuit, adding more resistors increases total resistance and thus lowers current. But the opposite is true in a parallel circuit because adding more resistors in parallel creates more choices and lowers total resistance. If the same battery is connected to the resistors, current will increase.

Explanation:

8 0

3 years ago

Some life forms move so slowly that their movement can not be detected by normal observation the best way to determine any movem

yaroslaw [1]

because the form can be watched over a long time for deviations from the mark.

like fingernails, the grow slowly too. after a time, they get clipped

6 0

3 years ago