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3 years ago

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Describe how cell membranes are selectively permeable

1 answer:

attashe74 [19]3 years ago

5 0

<span>Cell membranes are selectively permeable because it allows some things to enter or leave the cell while keeping other things outside or inside the cell.</span>

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What is the formula of the compound between calcium and sulfur that has the percent composition 55.6?

Yanka [14]

CaS is the empirical formula of the compound between calcium and sulphur that has the percent composition 55.6.

When percentages are given, we take a total mass of 100 grams.

Therefore the mass of each element is equal to the percentage given.

Mass of Ca = 55.6 g (given) of

S Mass = 44.4 g (100 - 55.6 = 44.4)

Step 1: Convert the given mass to moles.

moles Ca = given mass Ca / molar mass Ca

moles = 55.6 / 40 = 1.39 moles

mol S = specific mass S / molar mass S

mol = 44.4 / 32 = 1.39 mol

Step 2: Divide the molar ratio of each molar value by the smallest number of moles calculated.

For Ca = 1.39 / 1.39 = 1

For S = 1.39 / 1.39 = 1

The ratio of Ca : S = 1:1

Hence the empirical formula of the given compound will be CaS.

Learn more about empirical formula here : brainly.com/question/1496676

#SPJ4

8 0

1 year ago

Massive stars terminate in a brilliant explosion called a

BigorU [14]

super nova is named for such explosion

6 0

3 years ago

A car is moving at 30.0 km/h when it accelerates at 2.0 m/s for 3.6 s. what is the car final speed?

Lana71 [14]

Answer:

wrong question

Explanation:

unit of acceleration is written in m/s which is wrong

3 0

4 years ago

4. A 1200 kg car traveling North at 20.0 m/s collides with a 1400 kg car traveling South at 22.0 m/s. The two

Dvinal [7]

Answer:-2.61 m/s

Explanation:

This problem can be solved by the Conservation of Momentum principle, which establishes that the initial momentum $p_{o}$ must be equal to the final momentum $p_{f}$ :

$p_{o}=p_{f}$ (1)

Where:

$p_{o}=mV_{o}+MU_{o}$ (2)

$p_{f}=(m+M)V_{f}$ (3)

$m=1200 kg$ is the mass of the first car

$V_{o}=20 m/s$ is the velocity of the first car, to the North

$M=1400 kg$ is the mass of the second car

$U_{o}=-22 m/s$ is the mass of the second car, to the South

$V_{f}$ is the final velocity of both cars after the collision

$mV_{o}+MU_{o}=(m+M)V_{f}$ (4)

Isolating $V_{f}$ :

$V_{f}=\frac{mV_{o}+MU_{o}}{m+M}$ (5)

$V_{f}=\frac{(1200 kg)(20 m/s)+(1400 kg)(-22 m/s)}{1200 kg+1400 kg}$ (6)

Finally:

$V_{f}=-2.61 m/s$ (7) This is the resulting velocity of the wreckage, to the south

7 0

4 years ago

A rubbit gets down from a rump which its /\x=0.85m in 0.5s, The rubbit's mass is 2kg, what is the net Force?

Ira Lisetskai [31]

Answer: 13.6 N

Explanation:

The equation of motion for the rabbit is:

$\Delta x=V_{ox}t+\frac{1}{2}a_{x}t^{2}$ (1)

Where:

$\Delta x=0.85 m$ is the distance traveled by the rabbit

$V_{ox}=0 m/s$ is the rabbit's initial velocity, assuming it started from rest

$t=0.5 s$ is the time

$a_{x}$ is the acceleration

Isolating $a_{x}$ :

$a_{x}=\frac{2 \Delta x}{t^{2}}$ (2)

$a_{x}=\frac{2 (0.85 m)}{(0.5)^{2}}$ (3)

$a_{x}=6.8 m/s^{2}$ (4)

On the other hand, the force $F_{x}$ is given by:

$F_{x}=m.a_{x}$ (5)

Where $m=2 kg$ is the mass of the rabbit

Substituting (4) in (5):

$F_{x}=(2 kg)(6.8 m/s^{2})$ (6)

Finally:

$F_{x}=13.6 N$

6 0

3 years ago