1. How many MOLECULES are contained in 80.0 grams of sodium hydroxide?

Use the following balanced reaction to solve:

Naily [24]

Answer: 60.7 g of $PH_3$ will be formed.

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given volume}}{\text{Molar volume}}$

$\text{Moles of} H_2=\frac{60L}{22.4L}=2.68moles$

The balanced chemical reaction is

$P_4(s)+6H_2(g)\rightarrow 4PH_3(g)$

$H_2$ is the limiting reagent as it limits the formation of product and $P_4$ is the excess reagent.

According to stoichiometry :

6 moles of $H_2$ produce = 4 moles of $PH_3$

Thus 2.68 moles of $H_2$ will produce= $\frac{4}{6}\times 2.68=1.79moles$ of $PH_3$

Mass of $PH_3=moles\times {\text {Molar mass}}=1.79moles\times 33.9g/mol=60.7g$

Thus 60.7 g of $PH_3$ will be formed by reactiong 60 L of hydrogen gas with an excess of $P_4$

3 0

3 years ago

In the second step of this reaction, isocyanic acid reacts to form melamine and carbon dioxide: HNCO(l)→C3N3(NH2)3(l)+CO2(g) Bal

kykrilka [37]

Answer:

The coefficients are 6, 1, 3

Explanation:

HNCO →C3N3(NH2)3 + CO2

From the above equation, there are a total of 6 atoms of nitrogen on the right side and 1atom on the left. It can be balance by putting 6 in front of HNCO as shown below:

6HNCO → C3N3(NH2)3 + CO2

Now there are 6 atoms of carbon on the left side and 4 atoms on the right side. It can be balance by putting 3 in front of CO2 as shown below:

6HNCO → C3N3(NH2)3 + 3CO2

Now the equation is balanced as the numbers of atoms of the different elements on both sides of the equation are the same.

The coefficients are 6, 1, 3

8 0

3 years ago

Which of the following statements is TRUE? Which of the following statements is TRUE? Two electrons in the same orbital can have

Monica [59]

An orbital that penetrates into the region occupied by core electrons is less shielded from nuclear charge than an orbital that does not penetrate and therefore has a lower energy.

Explanation:

The only true statement from the given options is that "an orbital that penetrates into the region occupied by core electrons is less shielded from nuclear charge than an orbital that does not penetrate and therefore has a lower energy." Inner orbitals which are also known to contain core electrons feels the bulk of the nuclear pull on them compared to the outermost orbitals containing the valence electrons.

The nuclear pull is the effect of the nucleus pulling and attracting the electrons in orbitals.
This pull is stronger for inner orbitals and weak on the outer ones.
The outer orbitals are said to be well shielded from the pull of the nuclear charge.
Also, based on the quantum theory, electrons in the outer orbitals have higher energies because they occupy orbitals at having higher energy value.

Learn more:

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8 0

3 years ago

A chemical equation is shown below. KNO3 → KNO2 + O2 What are the coefficients that should be added to balance this equation? Us

uysha [10]

20) Balanced chemical equation: 2KNO₃ → 2KNO₂ + O₂.

Potassium nitrate is decomposed on potassium nitrite and oxygen.

According to principle of mass conservation, number of atoms must be equal on both side of chemical reaction.

There are two potassium atoms, two nitrogen atoms and six oxygen atoms on both side of balanced chemical reaction.

Decomposition is reaction where one substance (in this example potassium nitrate) is broken down into two or more simpler substances (potassium nitrite and oxygen).

21) The answer is:

Balanced chemical reaction: double recplacement reaction.

MgCl₂(aq) + Na₂CO₃(aq) → MgCO₃(s) + 2NaCl(aq).

The magnesium (Mg) and the sodium (Na) replace each other making this a double replacement reaction.

Reactivity series is an empirical progression of a series of metals, arranged by their reactivity from highest to lowest (alkaline metals have highest reactivity and Noble metals lowest reactivity):

K > Ba > Sr > Na > Ca > Mg > Be > Al > Mn > Zn > Cr> Fe > Cd > Co > Ni > Sn > Pb > H(in acids) > Cu > Hg > Ag.

Metal higher in the reactivity series will displace another and it will be oxidized.

Magnesium is higher it this series than aluminium and aluminium is higher than copper.

22) The answer is: half life is 22 years.

Half-life is the time required for a quantity (in this example mass of the element) to reduce to half its initial value and is independent of initial concentration.

Mass of the element is reduced by half in 22 years from 45 grams to 22.5 grams.

First calculate the radioactive decay rate constant λ:

λ = 0.693 ÷ t.

λ = 0.693 ÷ 22 y.

λ = 0.0315 1/y.

ln(m/m₀) = -λ·t₁.

ln(4.8125/308) = -0.0315 1/y · t₁.

t₁ = 132.02 y.

7 0

3 years ago

What happens when two hydrogen atoms enter the ETS as part of either NADH or FADH2?

murzikaleks [220]

I'm pretty sure its D

7 0

3 years ago

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