22 °C to K (approximate room temperature)

Whitepunk [10]

Atomic mass Calcium = 40.078 a.m.u

40.078 g ---------------- 6.02x10²³ atoms
165 g -------------------- ??

165 x ( 6.02x10²³) / 40.078 => 2.47x10²⁴ atoms

hope this helps!

4 0

3 years ago

The accepted value for the mass of a moonrock is 46.37 g. In an experiment the rock is measured to be 47.25 g. What is the perce

Artist 52 [7]

Answer:

The answer is

Explanation:

The percentage error of a certain measurement can be found by using the formula

$P(\%) = \frac{error}{actual \: \: number} \times 100\% \\$

From the question

actual measurement = 46.37 g

error = 47.25 - 46.37 = 0.88

The percentage error of the measurement is

$P(\%) = \frac{0.88}{46.37} \times 100 \\ = 1.89777873...$

We have the final answer as

Hope this helps you

4 0

3 years ago

A PNP transistor is connected in a circuit so that the collector-base junction remains reverse biased and the emitter-base junct

maw [93]

Here are the choices:

A. the output current will be much smaller than the input current.
B. the output voltage will be much larger than the input voltage. 
C. the output voltage will be much smaller than the input voltage. 
D. the output current will be much larger than the input current

The correct answer is letter B. the output voltage will be much larger than the input voltage.

5 0

4 years ago

Problem PageQuestionSteam reforming of methane ( ) produces "synthesis gas," a mixture of carbon monoxide gas and hydrogen gas,

Serhud [2]

The question is incomplete. Her eis the complete question.

Steam reforming methane (CH4) produces "synthesis gas", a mixture of carbon monoxide gas and hydrogen gas, which is the starting point for many important industrial chemical syntheses. An industrial chemist studying this reaction fills a 125L tank with 20 mol of methane gas and 10 mol of water vapor at 38°C. He then raises the temperature, and when the mixture has come to equilibrium measures the amount of gas hydrogen to be 18 mol. Calculate the concentration equilibrium constant for the steam reforming of methane at the final temperature of the mixture. Round your answer to significant digits.

Answer: $K_{c}$ = 2. $10^{-2}$

Explanation: The reaction for steam reforming methane is:

$CH_{4} + H_{2}O$ ⇒ $CO_{} + 3H_{2}$

To calculate the concentration equilibrium constant, first calculate the molarity ( $\frac{mol}{L}$ ) of each molecule of the reaction.

At 38°C: At the initial temperature, there no products yet

Molarity of CH4:

CH4 = $\frac{20}{125}$ = 0.16M

Molarity of H20:

H2O = $\frac{10}{125}$ = 0.08M

At final temperature:

Molarity of H2:

H2 = $\frac{18}{125}$ = 0.144M

According to the chemical reaction, the combination of 1 mol of each reagents produces 1 mol of CO and 3 mols of H2, so, for the products, the ratio is 1:3.

Molarity of CO:

CO = $\frac{0.144}{3}$ = 0.048M