Which terms describe a substance that has a low melting point and poor electrical conductivity?

How many grams of H2SO4 are needed to prepare 500. mL of a .250M solution?

zavuch27 [327]

Answer:

We need 12.26 grams H2SO4

Explanation:

Step 1: Data given

Volume of a H2SO4 solution = 500 mL = 0.500 L

Concentration of the H2SO4 solution = 0.250 M

Molar mass of H2SO4 = 98.08 g/mol

Step 2: Calculate moles H2SO4

Moles H2SO4 = concentration * volume

Moles H2SO4 = 0.250 M * 0.500 L

Moles H2SO4 = 0.125 moles

Step 3: Calculate mass of H2SO4

Mass of H2SO4 = moles * molar mass

Mass of H2SO4 = 0.125 moles * 98.08 g/mol

Mass of H2SO4 = 12.26 grams

We need 12.26 grams H2SO4

7 0

3 years ago

onvert the value of Kc to a value of Kp for the following reaction: N2(g)+3H2(g)⇌2NH3(g) Kc = 0.50 at 400 °C.

ale4655 [162]

Answer:

$K_p= 0.00016$

Explanation:

The relation between Kp and Kc is given below:

$K_p= K_c\times (RT)^{\Delta n}$

Where,

Kp is the pressure equilibrium constant

Kc is the molar equilibrium constant

R is gas constant

T is the temperature in Kelvins

Δn = (No. of moles of gaseous products)-(No. of moles of gaseous reactants)

For the first equilibrium reaction:

$N_2_{(g)}+3H_2_{(g)}\rightleftharpoons2NH_3_{(g)}$

Given: Kc = 0.50

Temperature = $400^oC=[400+273]K=673K$

R = 0.082057 L atm.mol⁻¹K⁻¹

Δn = (2)-(3+1) = -2

Thus, Kp is:

$K_p= 0.50\times (0.082057\times 673)^{-2}$

$K_p= 0.00016$

6 0

2 years ago

The thin outer layer of Earth, called the crust, contains only 0.50 percent of Earth's total mass and yet is the source of almos

Rzqust [24]

Answer:

The mass of silicon in kilograms in Earth's crust is $7.2729\times 10^{21} kg$ .

Explanation:

Mass of Earth = $5.9\times 10^{21} tons$

(1 ton= 2000 lb)

(1 lb =453.6 g)

1 ton = 2000 × 453.6 g =907,200 g

Mass of Earth = $5.9\times 10^{21}\times 907,200 g=5.3524\times 10^{27} g$

Percentage of earth crust = 0.50%

Mass of earth crust = M

$0.50\%=\frac{M}{5.3524\times 10^{27}}\times 100$

$M=2.6762\times 10^{25} g$

Percentage of the silicon in Earth's crust = 27.2 %

Mass of silicon in in Earth's crust = m

$Si\%=\frac{m}{M}\times 100$

$27.2\%=\frac{m}{2.6762\times 10^{25} g}\times 100$

$m = 7.2792\times 10^{24} g=7.2729\times 10^{21} kg$

1000 g = 1 kg

The mass of silicon in kilograms in Earth's crust is $7.2729\times 10^{21} kg$ .

7 0

3 years ago

Why do you think that scientists in the 20th century thought that it was important to “unlock” the structures of the atom?

Soloha48 [4]

Answer:

The 20th century saw huge advances in our understanding and use of the nucleus. For instance, in 1939 scientists Otto Hahn, Lise Meitner and Otto Frisch discovered nuclear fission – a process by which radioactive materials release energy when they are induced to split.

Realising the huge amount of energy that such a reaction produces, scientists were tasked with developing this new knowledge initially for harm in nuclear weapons. Just six years after fission’s discovery, it was harnessed in the atom bombs that destroyed the Japanese cities Hiroshima and Nagasaki, and controversially ended the Second World War. Later, much more powerful hydrogen bombs were developed that combined fission with the process powering the Sun – fusion.

Hope this helps! PLEASE GIVE ME BRAINLIEST!!!!! =)

7 0

3 years ago

Which of the following statements is true based on the propositions of the kinetic molecular theory?

Delvig [45]

The answer is 4.
Gases have low densities, because of the increased space between hight-energy particles.

6 0

2 years ago

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