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3 years ago

Fill in the coefficient needed to make the equation balanced.

Chemistry

1 answer:

Natali [406]3 years ago

4 0

Answer:

1 a

2 b

3 a

4. c

Explanation:

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Which of the following choices is a sign that a glacier was present at one point in history?

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answer:

B. U-shaped valleys

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3 years ago

1. The motion of an object with constant acceleration is also known as ________. *

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Answer:

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Explanation:

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3 years ago

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

vesna_86 [32]

Explanation:

Relation between pressure, latent heat of fusion, and change in volume is as follows.

$\frac{dP}{dT} = \frac{L}{T \times \Delta V}$

Also, $\frac{L}{T} = \Delta S^{fusion}_{m}$

where, $\Delta V^{fusion}_{m}$ is the difference in specific volumes.

Hence, $\frac{dP}{dT} = \frac{\Delta S^{fusion}_{m}}{\Delta V^{fusion}_{m}}$

As, $\Delta S^{fusion}_{m} = \frac{L}{T} = \frac{6010}{273.15}$ = 22.0 J/mol K

And, $\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$ ...... (1)

where, $d_{H_{2}O}$ = density of water

$d_{ice}$ = density of ice

M = molar mass of water = $18.02 \times 10^{-3} kg$

Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.

$\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$

= $\frac{18.02 \times 10^{-3}}{997} - \frac{18.02 \times 10^{-3}}{920}$

= $-1.51 \times 10^{-6}$

Therefore, calculate the required pressure as follows.

$\frac{dP}{dT} = \frac{22}{-1.51 \times 10^{-6}}$

= $1.45 \times 10^{7} Pa/K$

or, = 145 bar/K

Hence, for change of 1 degree pressure the decrease is 145 bar and for 4.7 degree change dP = $145 \times 4.7 bar$

= 681.5 bar

Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.

5 0

3 years ago

How many grams of h2 are needed to produce 14.51 g of nh3?

gavmur [86]

Answer:

2.57 g of H₂

Solution:

The Balance Chemical Equation is as follow,

N₂ + 3 H₂ → 2 NH₃

According to Balance equation,

34.06 g (2 moles) NH₃ is produced by = 6.04 g (3 moles) of H₂

So,

14.51 g of NH₃ will be produced by = X g of H₂

Solving for X,

X = (14.51 g × 6.04 g) ÷ 34.06 g

X = 2.57 g of H₂

7 0

3 years ago

Calculate the oxidation state of the underlined elements of K2 Cr2 O7

Semenov [28]

Answer:

Explanation:

In PbO2, oxygen exhibits an oxidation number of -2 (since it's not a peroxide or superoxide):

Let the oxidation number of Pb be x. Then, for the compound to be neutral, the oxidation numbers of all atoms should add up to zero.

⇒ x + (−2) + (−2) = 0

x = +4

So the oxidation no. of Pb is +4.

I hope this helps.

3 0

2 years ago