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3 years ago

Mass in grams of 4.26 mol Si

Chemistry

2 answers:

Brrunno [24]3 years ago

7 0

Answer/ explanation :

Mass in grams of 4.26 mol of Si.

To calculate this, we use the formula

Number of mole = mass / molar mass

Since we are given the number of mole

Number of mole = 4.26mol

Mass = ?g

Molar mass of Si = 28.0855g/mol

4.26mol = mass / 28.0855g/mol

By cross multiplication,

Mass = 4.26 * 28.0855

= 119.644g

Therefore, the number of mass in gram of Si is 119.644g

Whitepunk [10]3 years ago

6 0

Answer:

119.28g

Explanation:

Data obtained from the question include:

Number of mole of Si = 4.26 mol

Molar Mass of Si = 28g/mol

Mass of Si =?

Number of mole = Mass /Molar Mass

Mass = number of mole x molar Mass

Mass of Si = 4.26 x 28

Mass of Si = 119.28g

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A beaker is filled to the 500 mL mark with alcohol. What increase in volume (in mL) does the beaker contain when the temperature

Aliun [14]

Answer:

"1.4 mL" is the appropriate solution.

Explanation:

According to the question,

$v_0=500$
$\alpha =1.12\times 10^{-4}$
$\Delta \epsilon = 25$

Now,

Increase in volume will be:

⇒ $\Delta V = \alpha\times v_0\times \Delta \epsilon$

By putting the given values, we get

$=1.12\times 10^{-4}\times 500\times 25$

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3 years ago

Assume that your empty crucible weighs 15.98 g, and the crucible plus the sodium bicarbonate sample weighs 18.56 g. After the fi

Savatey [412]

The question is incomplete, the complete question is;

Assume that your empty crucible weighs 15.98 g, and the crucible plus the sodium bicarbonate sample weighs 18.56 g. After the first heating, your crucible and contents weighs 17.51 g. After the second heating, your crucible and contents weighs 17.50 g.

What is the theoretical yield of sodium carbonate?

What is the experimental yield of sodium carbonate?

What is the percent yield for sodium carbonate?

Which errors could cause your percent yield to be falsely high, or even over 100%?

Answer:

See Explanation

Explanation:

We have to note that water is driven away after the second heating hence we are concerned with the weight of the pure dry product.

Hence;

From the reaction;

2 NaHCO3 → Na2CO3(s) + H2O(l) + CO2(g)

Number of moles of sodium bicarbonate = 18.56 - 15.98 = 2.58 g/87 g/mol

= 0.0297 moles

2 moles of sodium bicarbonate yields 1 mole of sodium carbonate

0.0297 moles of 0.015 moles sodium bicarbonate yields 0.0297 * 1/2 = 0.015 moles

Theoretical yield of sodium carbonate = 0.015 moles * 106 g/mol = 1.59 g

Experimental yield of sodium bicarbonate = 17.50 g - 15.98 g = 1.52 g

% yield = experimental yield/Theoretical yield * 100

% yield = 1.52/1.59 * 100

% yield = 96%

The percent yield may exceed 100% if the water and CO2 are not removed from the system by heating the solid product to a constant mass.

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2 years ago

You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. Y

lbvjy [14]

Answer: 2.58 days

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = ?

t = age of sample = 6 days

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a - x = amount left after decay process = 0.2 g

a) to find the rate constant

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$k=\frac{2.303}{6}\log\frac{1.0}{0.2}$

$k=0.268days^{-1}$

b) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

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gulaghasi [49]

Answer:

The strength of a bond between two atoms increases as the number of electron pairs in the bond increases.

Explanation:

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Deffense [45]

Answer:

Explanation:

final temperature of the cube

initial temperature of the cube

mass of the cube

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