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3 years ago

What is 9,865 km expressed in scientific notation? A. 9.865 × 100 km B. 9.865 × 102 km C. 9.865 × 103 km D. 9.865 × 10-3 km

Chemistry

1 answer:

joja [24]3 years ago

6 0

Answer:

A scientific notation is when a number is between 1 and 10 times a power of 10. Your answer will probably be 9.865 x 10³ km or 9.865.

Go for C (?)

Sorry it's hard for me to read with the layout heh...

-Hope this helps

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7. How many liters of NH3, at STP, will react with 5.3 g 02 to form NO2 and water? (1 point)

motikmotik

Answer:

2.12 L

Explanation:

Data Given:

Amount of O₂ = 5.3 g

Amount of NH₃ = ?

Given Reaction:

4NH₃ + 7O₂ ----------> 4NO₂ +6H₂O

Solution:

for details first we look into the reaction

4NH₃ + 7O₂ ----------> 4NO₂ + 6H₂O

4 mole 7 mol

from reaction we come to know that 4 mole of NH₃ react with 7 mole of O₂

Now we have to convert moles of NH₃ to Liter and mole of O₂ to grams

To convert moles of NH₃ to Liter formula will use

Volume of NH₃ = no. of moles x molar volume at STP

molar volume at STP = 22.4 L/mol

put values in above equation

Volume of NH₃ = 4 mol x 22.4 L/mol

Volume of NH₃ = 89.6 L

Now,

To convert moles of O₂ to grams

mass of O₂ = no. of moles x molar mass

molar mass of O₂ = 2(16) = 32 g/mol

Put values in above equation

mass of O₂ = 7 moles x 32 g/mol

mass of O₂ = 224 g

So,

We come to know that 89.6 L of NH₃ react with 224 g of O₂ to give NO₂ and water then how many liters of NH₃ will react with 5.3 g O₂

Now apply unity formula

89.6 L of NH₃ ≅ 224 g of O₂

X L of NH₃ ≅ 5.3 g of O₂

Do cross multiplication

Liter of NH₃ = 89.6 L x 5.3g / 224 g

Liter of NH₃ = 2.12 L

option 2 is correct that is 2.12 Liter of NH₃ will react with 5.3 g O₂

8 0

4 years ago

Which of the following does not describe a characteristic of carbon?

anastassius [24]

The characteristic that is not descriptive of C, would be D. It forms bonds with only itself. It forms bonds with almost all other nonmetals, present, like H,O,N, etc.

7 0

3 years ago

Read 2 more answers

Which of the graphs below might represent a mixture of pure water and ice exposed to a room temperature of 3°C?

Y_Kistochka [10]

Answer:

C. Graph C

Explanation:

We have a mixture of water and ice.

At 0 °C they are at equilibrium.

water-to-ice rate = ice-to-water rate

Next, we lower the temperature to -3 °C — just slightly below freezing.

The water will slowly turn to ice.

The water-to-ice rate will be slightly faster than the ice-to-water rate.

The purple bar will be slightly higher than the blue bar.

Graph C best represents the relative rates

A. is wrong. The ice-to-water rate is faster, so the water is melting. The temperature is slightly above freezing (say, 3 °C).

B. is wrong. The two rates are equal, so the temperature is 0 °C.

D. is wrong. The water-to-ice rate (freezing) is much greater than the ice-to-water rate, so the temperature is well below freezing( say, -10 °C).

6 0

4 years ago

1) If 0.193 grams of toluene is dissolved in 2.532 grams of p-xylene, what is the molality of toluene in the solution?2) If a fr

AveGali [126]

Answer:

The value of $K_f$ for xylene is 4.309°C/m.

The molar mass of pentane using this data is 73.82 g/mol.

Explanation:

$\Delta T_f=K_f\times \frac{\text{Amount of solute}}{\text{Molar mass of solute}\times \text{Mass of solvent(kg)}}$

where,

$\Delta T_f$ =depression in freezing point

$K_f$ = freezing point constant

we have :

1) freezing point constant for xylene = $K_f$ =?

Mass of toluene = 0.193 g

Mass of xylene = 2.532 kg = 0.002532 kg ( 1 g =0.001 kg)

$\Delta T_f=3.57^oC$

$3.57^oC=K_f\times \frac{0.193 g}{92 g/mol\times 0.002532 kg}$

$K_f=4.309^oC/m$

The value of $K_f$ for xylene is 4.309°C/m.

Mass of pentane = 0.123 g

molar mass of pentame= M

Mass of xylene = 2.493 g = 0.002493 kg

Freezing point Constant of xylene = $K_f=4.309^oC/m$

$2.88^oC=4.309^oC/m\times \frac{0.123g}{M\times 0.002493 kg}$

M = 73.82 g/mol

The molar mass of pentane using this data is 73.82 g/mol.

5 0

4 years ago

Complete the chart below.

omeli [17]

Answer:

Deformation of heat and pressure

Explanation:

It is deformation of heat and pressure because igneous rock is made by magma when it cools. After a long time and pressure, it will turn into sedimentary rock.

6 0

4 years ago