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3 years ago

According to Archimedes' principle, when will an object float in water?

Physics

2 answers:

Vladimir79 [104]3 years ago

5 0

Answer:

Its B

Explanation:

a p e x

Elena-2011 [213]3 years ago

3 0

C. When it’s density is greater than the density of water.

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Automobile air bags use the decomposition of sodium azide as their sources of gas for rapid inflation, represented in the reacti

NeTakaya

Answer : The mass of $NaN_3$ required is 71.175 grams.

Explanation :

To calculate the moles of nitrogen gas, we use the equation given by ideal gas :

PV = nRT

where,

P = Pressure of nitrogen gas = 763 torr

V = Volume of the nitrogen gas = 40.0 L

n = number of moles of gas = ?

R = Gas constant = $62.364\text{ L.torr }mol^{-1}K^{-1}$

T = Temperature of helium gas = $25^oC=273+25=298K$

Putting values in above equation, we get:

$763torr\times 40.0L=n\times 62.364\text{ L.torr }mol^{-1}K^{-1}\times 298K\\\\n=1.642mol$

Now we have to calculate the moles of $NaN_3$ .

The balanced chemical reaction is:

$2NaN_3(s)\rightarrow 2Na(s)+3N_2(g)$

From the balanced chemical reaction, we conclude that

As, 3 moles of $N_2$ produced from 2 moles $NaN_3$

So, 1.642 moles of $N_2$ produced from $\frac{2}{3}\times 1.642=1.095$ moles $NaN_3$

Now we have to calculate the mass of $NaN_3$ .

Molar mass of $NaN_3$ = 65 g/mol

$\text{Mass of }NaN_3=\text{Moles of }NaN_3\times \text{Molar mass of }NaN_3$

$\text{Mass of }NaN_3=1.095mole\times 65g/mole=71.175g$

Therefore, the mass of $NaN_3$ required is 71.175 grams.

5 0

4 years ago

Nuclear Reactions:<br> Please answer numbers 4,5,6.

Vikentia [17]

Answer:

4. ¹₁H + ¹³₆C —> ¹⁴₇N + γ

5. ¹₀n + ¹⁰₅B —> ⁷₃Li + ⁴₂He

6. ⁴₂He + ¹⁴₇N —> ¹⁷₈O + ¹₁H

Explanation:

4. ¹₁H + ¹³₆C —> ¹⁴₇N + __

Let ᵇₐX be the unknown.

Thus, the equation becomes:

¹₁H + ¹³₆C —> ¹⁴₇N + ᵇₐX

Next, we shall determine b, a and X. This is illustrated below:

For b:

1 + 13 = 14 + b

14 = 14 + b

Collect like terms

b = 14 – 14

b = 0

For a:

1 + 6 = 7 + a

7 = 7 + a

Collect like terms

a = 7 – 7

a = 0

Therefore,

ᵇₐX => ⁰₀X => γ

Thus, the balanced equation is

¹₁H + ¹³₆C —> ¹⁴₇N + γ

5. ¹₀n + ¹⁰₅B —> __ + ⁴₂He

Let ˣᵧA be the unknown.

Thus, the equation becomes:

¹₀n + ¹⁰₅B —> ˣᵧA + ⁴₂He

Next, we shall determine x, y and A. This can be obtained as follow:

For x:

1 + 10 = x + 4

11 = x + 4

Collect like terms

x = 11 – 4

x = 7

For y:

0 + 5 = y + 2

5 = y + 2

Collect like terms

y = 5 – 2

y = 3

Therefore,

ˣᵧA =>⁷₃A => ⁷₃Li

Thus, the balanced equation is:

¹₀n + ¹⁰₅B —> ⁷₃Li + ⁴₂He

6. ⁴₂He + ¹⁴₇N —> __ + ¹₁H

Let ᶜₑG be the unknown.

Thus, the equation becomes:

⁴₂He + ¹⁴₇N —> ᶜₑG + ¹₁H

Next, we shall determine c, e and G. This can be obtained as follow:

For c:

4 + 14 = c + 1

18 = c + 1

Collect like terms

c = 18 – 1

c = 17

For e:

2 + 7 = e + 1

9 = e + 1

Collect like terms

e = 9 – 1

e = 8

Therefore,

ᶜₑG => ¹⁷₈G => ¹⁷₈O

Thus, the balanced equation is:

⁴₂He + ¹⁴₇N —> ¹⁷₈O + ¹₁H

8 0

3 years ago

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going

4vir4ik [10]

Answer:

B. The force would be the same in both cases.

Explanation:

According to Newton's 3rd law where impulse was equated to the momentum formula.

F × t = M × V

where,

Force = F

V = velocity

Since, Impulse is force multiplied by time, whereas the time of contact is the same for both, therefore the impulse is the same in magnitude for the two trucks.

Case 1: Hitting the other car

Case 2: Hitting the brick wall

In Case 1, both the cars are identical and have same velocity whereas in the Case 2, the wall is stationary.

The case of hitting the brick wall have the same impact force as hitting the other car, because they have the same change in momentum.

Therefore, The force would be the same in both cases.

6 0

4 years ago

What is the number N0 of 99mTc atoms that must be present to have an activity of 15mCi?

svetoff [14.1K]

Base on my research, within 2 hours you have a number of atoms which remain.
N= N0*2^(-t/6.020 = N= N0*2^-0.33223= 07943 N0

So, the number of atoms that are being disintegrated is N0-N=N0*(1-0.79430)=0.2057 N0

It must be equal to 15 mCi = 15*3.7*10^7= 5.55*10^8 atoms

N0= 5.55*10*8/0.2057 = 2.698*10^9 atoms

Therefore, 2.698*10^9 atoms is the number of N0

4 0

3 years ago

A space craft is traveling in interplanetary space at a constant velocity. what is the estimated distance traveled by the space

mina [271]

Answer:

A. 2.30 x 10^2 kil

Explanation:

3/2 = 1.5 and 0.72/2 = 0.36

1.93 + 0.36 = 2.29

2.29 = about 2.30

7 0

3 years ago