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3 years ago

Which of the following pairs are about equal in mass?

Chemistry

2 answers:

Mademuasel [1]3 years ago

3 0

Answer:

Proton and neutrons

Explanation:

they both have a mass of 1 amu or 1 atomic mass

Gennadij [26K]3 years ago

3 0

Answer:

C. Proton and Neutron

Explanation:

Their atomic mass units are nearly similar in size.

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What is an example of a neutral ion.

VARVARA [1.3K]

A neural sodium ion.

4 0

3 years ago

How many cu atoms are present in a piece of sterlingsilver jewelry weighing 33.24 g ? (sterling silver is a silver–copper alloy

emmasim [6.3K]

The mass of piece of sterling silver jewelry is 33.24 g. It contains 92.5% silver Ag by mass. Since, sterling silver is an alloy of Ag-Cu thus, percentage of Cu will be:

% Cu=100-92.5=7.5%

Thus, mass of copper will be:

$m_{Cu}=\frac{7.5}{100}\times 33.24 g=2.493 g$

Molar mass of Cu is 63.546 g/mol, thus, number of moles of Cu can be calculated as follows:

$n=\frac{m}{M}$

Here, m is mass and M is molar mass.

Putting the values,

$n=\frac{2.493 g}{63.546 g/mol}=0.03923 mol$

Now, in 1 mole of Cu there are $6.303\times 10^{23}atoms$ thus, in 0.03923 mol, number of Cu atoms will be:

$0.03923 mol\times 6.303\times 10^{23}atoms=2.363\times 10^{22} atoms$

Thus, number of atoms of Cu will be $2.363\times 10^{22} atoms$ .

8 0

3 years ago

3 H2 (g) + N2 (g) 2 NH3 (g)

ale4655 [162]

Answer:

Mass = 0.697 g

Explanation:

Given data:

Volume of hydrogen = 1.36 L

Mass of ammonia produced = ?

Temperature = standard = 273.15 K

Pressure = standard = 1 atm

Solution:

Chemical equation:

3H₂ + N₂ → 2NH₃

First of all we will calculate the number of moles of hydrogen:

PV = nRT

R = general gas constant = 0.0821 atm.L/mol.K

1atm ×1.36 L = n × 0.0821 atm.L/mol.K × 273.15 K

1.36 atm.L = n × 22.43 atm.L/mol

n = 1.36 atm.L / 22.43 atm.L/mol

n = 0.061 mol

Now we will compare the moles of hydrogen and ammonia:

H₂ : NH₃

3 : 2

0.061 : 2/3×0.061 = 0.041

Mass of ammonia:

Mass = number of moles × molar mass

Mass = 0.041 mol × 17 g/mol

Mass = 0.697 g

4 0

3 years ago

The decomposition of NI3 to form N2 and I2 releases −290.0 kJ of energy. The reaction can be represented as 2NI3(s)→N2(g)+3I2(g)

EastWind [94]

Answer:

-7.34 kilo Joules is the change in enthaply when 20.0 grams of nitrogen triiodide decomposes.

Explanation:

Mass of nitrogen triiodide = 20.0 g

Moles of nitrogen triiodide = $\frac{20.0 g}{395 g/mol}=0.05063 mol$

$2NI_3(s)\rightarrow N_2(g)+3I_2(g), \Delta H_{rxn}=-290.0 kJ$

According to reaction, 2 moles of nitrogen triiodide gives 290.0 kilo Joules of heat on decomposition ,then 0.05063 moles of nitrogen triiodide will give :

$\frac{-290.0 kJ}{2}\times 0.05063=-7.34 kJ$

-7.34 kilo Joules is the change in enthaply when 20.0 grams of nitrogen triiodide decomposes.

3 0

3 years ago

What is an example of reactivity?

Vedmedyk [2.9K]

Reactivity is an impetus For which a chemical substance undergoes A chemical either by itself or with another materialWith an overall release of energy

4 0

2 years ago