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4 years ago

Which is a pure substance helium in a balloon

Chemistry

1 answer:

11Alexandr11 [23.1K]4 years ago

3 0

Answer:

An element is a pure substance as well, because if we fill up a balloon with just helium gas ,it will only contain helium atoms

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Which is a symbol that represents SI units for temperature.

dsp73

Answer:

A.'C

Explanation:

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5 0

4 years ago

Read 2 more answers

If 1.2 kilograms of rust forms on a bridge in 5 days, what should be the rate of reaction in grams per hour?

Dimas [21]

We have 1.2 kg of rust whithin 5 days.
the rate of reaction in grams per hour:

1.2 kg/5 day * 1000 g/kg * 1 day/24 hours = 10.0 grams/hour

hope this help

8 0

4 years ago

A 0.211 g sample of carbon dioxide, CO2, has a volume of 560 mL and a pressure of 429 mmHg whats the temperature of the gas in K

SCORPION-xisa [38]

The temperature of the gas sample is 813 K.

<u>Explanation:</u>

We have to use the ideal gas equation to find the temperature of the gas sample.

The ideal gas equation is PV = nRT

Pressure, P = 429 mm Hg = 0.56 atm

Volume, V = 560 mL = 0.56 L

R = gas constant = 0.08205 L atm mol⁻¹K⁻¹

Mass = 0.211 g

Molar mass of carbon di oxide = 44.01 g / mol

Moles, n = $$\frac{given mass}{molar mass} = \frac{0.211 g}{44.01 g/mol}$

= 0.0047 mol

Now, we have to plugin the above values in the above equation, we will get the temperature as,

$$T= \frac{PV}{nR}$

T = $$\frac{0.56 \times 0.56}{0.08205 \times 0.0047}$

= 813 K

So the temperature of the gas sample is 813 K.

5 0

4 years ago

250 ml of seawater and we inked each molecule with pink color, then we mixed this 250 ml in the ocean. After mixing you took 250

Marysya12 [62]

Answer:

9.77 × 10⁹ molecules

Explanation:

Since the density of water is 1 g/cm³ = 1000 g/L

So, we find the mass of sea water in 250 mL = 0.250 L

We know density = mass/volume

mass = density × volume = 1000 g/L × 0.250 L = 250 g

Now we calculate the number of moles of sea water in 250 g, 250 mL of sea water.

number of moles n = mass of sea water,m/molar mass of water, M

molar mass of water, M = 18 g/moL

n = m/M = 250 g/18 g/mol = 13.89 mol

We now calculate the number of molecules present in the 250 mL of sea water.

n = N/N' where N = number of molecules, N' = avogadro's number = 6.022 × 10²³/mol

So,N =nN' = 13.89 mol × 6.022 × 10²³/mol = 8.36 × 10²⁴ molecules

Now, the volume of the ocean is 1.337 × 10¹⁸ m³ = 1.337 × 10¹⁵ L

Since the 250 mL sea water is mixed with the ocean, the number of molecules per liter is 8.36 × 10²⁴ molecules/1.337 × 10¹⁵ L = 6.25 × 10⁹ molecules/L

If we now take 250 mL out of the ocean, the number of molecules in this 250 mL will be 6.25 × 10⁹ molecules/L × 250 mL = 6.25 × 10⁹ molecules/L × 0.250 L = 9.77 × 10⁹ molecules.

So, we have 9.77 × 10⁹ molecules of pink molecules in the 250 mL after mixing in the ocean.

6 0

3 years ago

How many particles would be found in a 12.7g sample of ammonium carbonate

Semenov [28]

Answer: The sample of ammonium carbonate contains

0.560 mol NH

Explanation:The chemical formula for ammonium carbonate is

(

)

. The formula indicates that in one mole of ammonium carbonate, there are two moles of ammonium ions,

4 0

4 years ago