Which statement describes the ocean floor?

Fields of Study Alferd Wegener

adelina 88 [10]

Answer:

jjjj

Explanation:

7 0

2 years ago

Approximately how many ice cubes must melt to cool 650 milliliters of water from 29°C to 0°C? Assume that each ice cube contains

qwelly [4]

Answer : The number of ice cubes melt must be, 13

Explanation :

First we have to calculate the mass of water.

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}$

Density of water = 1.00 g/mL

Volume of water = 650 mL

$\text{Mass of water}=1.00g/mL\times 650mL=650g$

Now we have to calculate the heat released on cooling.

Heat released on cooling = $m\times c\times (T_2-T_1)$

where,

m = mass of water = 650 g

c = specific heat capacity of water = $4.18J/g^oC$

$T_2$ = final temperature = $29^oC$

$T_2$ = initial temperature = $0^oC$

Now put all the given values in the above expression, we get:

Heat released on cooling = $650g\times 4.18J/g^oC\times (29-0)^oC$

Heat released on cooling = 78793 J = 78.793 kJ (1 J = 0.001 kJ)

As, 1 ice cube contains 1 mole of water.

The heat required for 1 ice cube to melt = 6.02 kJ

Now we have to calculate the number of ice cubes melted.

Number of ice cubes melted = $\frac{\text{Total heat}}{\text{Heat for 1 ice cube}}$

Number of ice cubes melted = $\frac{78.793kJ}{6.02kJ}$

Number of ice cubes melted = 13.1 ≈ 13

Therefore, the number of ice cubes melt must be, 13

3 0

3 years ago

What was the half-life of a new isotope?

REY [17]

The half-life of any substance is the amount of time taken for half of the original quantity of the substance present to decay. The half-life of a radioactive substance is characteristic to itself, and it may be millions of years long or it may be just a few seconds.

In order to determine the half-life of a substance, we simply use:
t(1/2) = ln(2) / λ

Where λ is the decay constant for that specific isotope.

8 0

3 years ago

Hydrazine (N2H4), a rocket fuel , reacts with oxygen to form nitrogen gas and water vapor. The reaction is represented with the

lilavasa [31]

Answer:

D) 8.40 L H₂O(g).

Explanation:

The balanced equation for the mentioned reaction is:

2N₂H₄(l) + O₂(g) → N₂(g) + 2H₂O(g),

It is clear that 2.0 moles of N₂H₄ react with 1.0 mole of O₂ to produce 2.0 moles of N₂ and 2.0 moles of H₂O.

At STP, 4.20L of O₂ reacts with N₂H₄:

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication: 

1.0 mol of O₂ represents → 22.4 L.

??? mol of O₂ represents → 4.2 L.

∴ 4.2 L of O₂ represents = (1.0 mol)(4.2 L)/(22.4 L) = 0.1875 mol.

To find the no. of moles of H₂O produced:

Using cross multiplication:

1.0 mol of O₂ produce → 2.0 mol of H₂O, from stichiometry.

0.1875 mol of O₂ produce → ??? mol of H₂O.

∴ The no. of moles of H₂O = (2.0 mol)(0.1875 mol)/(1.0 mol) = 3.75 mol.

Again, using cross multiplication:

1.0 mol of H₂O represents → 22.4 L, at STP.

3.75 mol of H₂O represents → ??? L.

∴ The no. of liters of water vapor will be produced = (3.75 mol)(22.4 L)/(1.0 mol) = 8.4 L.

So, the right choice is: D) 8.40 L H₂O(g).

3 0

2 years ago

consider this reaction at equilibrium at a total pressure: 2h2o(g) o2(g) 2h2o2(g) suppose the volume of this system is twice its

Daniel [21]

The total pressure when the new equilibrium is stabilized is half of the initial pressure of the system.

The given chemical reaction at a stable equilibrium is,

2H₂O(g)+O₂(g) = 2H₂O₂(g)

According to the ideal gas equation,

PV = nRT

P is pressure,

V is volume,

n is moles

R is gas constant,

T is temperature.

Assuming the temperature is constant.

If the volume of the system is twice the initial volume then the total pressure at the new equilibrium can be found out as,

P₁V₁ = P₂V₂

Where, P₁ and V₁ are initial volume and pressure while P₂ and V₂ are final pressure and volume.

If V₂ = 2V₁,

P₂ = P₁/2

So, the final total pressure will be half of the initial pressure.

To know more about equilibrium, visit,

brainly.com/question/517289

#SPJ4

5 0

5 months ago