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2 years ago

Which laboratory activity involves a chemical change?

Chemistry

2 answers:

Darya [45]2 years ago

7 0

Answer:

It is the first one.

Explanation:

Because yeah.

ipn [44]2 years ago

5 0

Answer:

the answer is the first one (a)

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Mandelic Acid is an organic acid composed of carbon (63.15%), hydrogen (5.30%), and oxygen (31.55%). Its molar mass is 152.14 g/

Dafna1 [17]

Answer:

Empirical formula is C3H3O

Molecular formula C9H9O3

Explanation:

From the question given, we obtained the following data:

Carbon = 63.15%

Hydrogen = 5.30%

Oxygen = 31.55%

We can obtain the empirical and molecular formula by doing the following as illustrated in the attached file. Please see attachment for explanation.

3 0

3 years ago

Read 2 more answers

4. DBearded waste of Co-60 must be stored until it is no longer radioactive. Cobalt-60

Bingel [31]

464 g radioisotope was present when the sample was put in storage

<h3>Further explanation</h3>

Given

Sample waste of Co-60 = 14.5 g

26.5 years in storage

Required

Initial sample

Solution

General formulas used in decay:

$\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}$

t = duration of decay

t 1/2 = half-life

N₀ = the number of initial radioactive atoms

Nt = the number of radioactive atoms left after decaying during T time

Half-life of Co-60 = 5.3 years

Input the value :

$\tt 14.5=No.\dfrac{1}{2}^{26.5/5.3}\\\\14.5=No.\dfrac{1}{2}^5\\\\No=\boxed{\bold{464~g}}$

8 0

3 years ago

1.86 g H2 is allowed to react with 9.75 g N2 , producing 2.87g NH3.

svet-max [94.6K]

Answer:

(a) Theoretical Yield = 10.50 g

(b) %age yield = 27.33 %

Explanation:

Answer-Part-(a)

The balance chemical equation for the synthesis of Ammonia is as follow;

N₂ + 3 H₂ → 2 NH₃

Step 1: Calculating moles of N₂ as;

Moles = Mass / M/Mass

Moles = 9.75 g / 28.01 g/mol

Moles = 0.348 moles of N₂

Step 2: Calculating moles of H₂ as;

Moles = Mass / M/Mass

Moles = 1.86 g / 2.01 g/mol

Moles = 0.925 moles

Step 3: Finding Limiting reagent as;

According to equation,

1 mole of N₂ reacts with = 3 moles of H₂

So,

0.348 moles of N₂ will react with = X moles of H₂

Solving for X,

X = 3 mol × 0.348 mol / 1 mol

X = 1.044 mol of H₂

It shows that to consume 0.348 moles of N₂ completely we require 1.044 mol of Hydrogen while, as given in statement we are only provided with 0.925 moles of H₂ hence, hydrogen is limiting reagent. Therefore, H₂ will control the final yield.

Step 4: Calculating moles of Ammonia as,

According to equation,

3 mole of H₂ produces = 2 moles of NH₃

So,

0.925 moles of H₂ will produce = X moles of NH₃

Solving for X,

X = 2 mol × 0.925 mol / 3 mol

X = 0.616 mol of NH₃

Step 5: Calculating theoretical yield of Ammonia as,

Theoretical Yield = Moles × M.Mass

Theoretical Yield = 0.616 mol × 17.03 g/mol

Theoretical Yield = 10.50 g

Answer-Part-(b)

%age yield = Actual Yield / Theoretical Yield × 100

%age yield = 2.87 g / 10.50 g × 100

%age yield = 27.33 %

4 0

3 years ago

solniwko [45]

Answer:

Explanation:

With the given choices, A would be correct for this question. But, both liquids and gases have particles that are far apart so that they can fill their containers.

7 0

3 years ago

A gram of gasoline produces 45.0kJ of energy when burned. Gasoline has a density of 0.77/gmL. How would you calculate the amount

user100 [1]

Answer:

See below

Explanation:

45 kJ / gm * .77 gm / liter * 13 liter = _________ kJ

4 0

1 year ago