Please help me this is my last question

What is difference between groups and periods? 8th grade science idk what to put it under

d1i1m1o1n [39]

One is rows the other is columns

7 0

2 years ago

_Li + __F2 → _LIF How do I balance this?

Semmy [17]

Answer:

2Li + F₂ → 2LiF

Explanation:

The reaction expression is given as:

Li + F₂ → LiF

We are to balance the expression. In that case, the number of atoms on both sides of the expression must be the same.

Let use a mathematical approach to solve this problem;

Assign variables a,b and c as the coefficients that will balance the expression:

aLi + bF₂ → cLiF

Conserving Li: a = c

F: 2b = c

let a = 1, c = 1 and b = $\frac{1}{2}$

Multiply through by 2;

a = 2, b = 1 and c = 2

2Li + F₂ → 2LiF

5 0

3 years ago

Use this equation for the following problems: 2NaN3 --> 2Na+3N2

olchik [2.2K]

Answer:

1) 65.0

2) 16.434 L = 16434 mL.

Explanation:

2NaN₃ → 2Na + 3N₂,

It is clear from the balanced equation that 2.0 moles of NaN₃ are decomposed to 2.0 moles of Na and 3.0 moles of N₂.

Q1: How many grams of NaN₃ are needed to make 23.6L of N₂?

Density of N₂ = 0.92 g/L which means that every 1.0 L of N₂ contains 0.92 g of N₂.

Now, we can get the mass of N₂ in 23.6 L N₂ using cross multiplication:

1.0 L of N₂ contains → 0.92 g of N₂.

23.6 L of N₂ contains → ??? g of N₂.

∴ The mass of N₂ in 23.6 L of N₂ = (23.6 L)(0.92 g)/(1.0 L) = 21.712 g.

We can get the no. of moles of 23.6 L of N₂ (21.712 g) using the relation:

n = mass/molar mass = (21.712 g)/(28.0 g/mol) = 0.775 mol.

We can get the no. of moles of NaN₃ needed to produce 0.775 mol of N₂:

using cross multiplication:

2.0 moles of NaN₃ produce → 3.0 moles of N₂, from the balanced equation.

??? mol of NaN₃ produce → 0.775 moles of N₂.

∴ The no. of moles of NaN₃ needed = (2.0 mol)(0.775 mol)/(3.0 mol) = 0.517 mol.

Finally, we can get the grams of NaN₃ needed:

mass = no. of moles x molar mass = (0.517 mol)(65.0 g/mol) = 33.6 g.

Q2: How many mL of N₂ result if 8.3 g Na are also produced?

We need to get the no. of moles of 8.3 g Na using the relation:

n = mass/atomic mass = (8.3 g)/(22.98 g/mol) = 0.36 mol.

We can get the no. of moles of N₂ produced with 0.36 mol of Na:

using cross multiplication:

2.0 moles of Na produced with → 3.0 moles of N₂, from the balanced equation.

0.36 moles of Na produced with → ??? moles of N₂.

∴ The no. of moles of N₂ needed = (3.0 mol)(0.36 mol)/(2.0 mol) = 0.54 mol.

We can get the mass of 0.54 mol of N₂:

mass = no. of moles x molar mass = (0.54 mol)(28.0 g/mol) = 15.12 g.

Now, we can get the mL of 15.12 g of N₂:

using cross multiplication:

1.0 L of N₂ contains → 0.92 g of N₂, from density of N₂ = 0.92 g/L.

??? L of N₂ contains → 15.12 g of N₂.

∴ The volume of N₂ result = (1.0 L)(15.12 g)/(0.92 g) = 16.434 L = 16434 mL.

4 0

2 years ago

How many moles of a gas sample are in a 10.0 L container at 373 K and 203 kPa? the gas constant is 8.31 L -kPa/ mol-K.

Zepler [3.9K]

I believe the answer is 0.33

5 0

2 years ago

Read 2 more answers

A molecule has sp2 hybridization with 1 lone pair.... The electron pair geometry of this molecule is: ... The geometry of this m

MrRa [10]

Answer:

The electron pair geometry is Trigonal planar

Molecular geometry - Bent

Approximate bond angle - <120°

Explanation:

The valence shell electron pair repulsion theory enables us to predict the shapes of molecules based on the number of electron pairs present on the valence shell of the central atom and based on the hybridization state of the central atom.

sp2 hybridization corresponds to trigonal planar geometry. Let us recall that the presence of lone pairs causes a deviation of the molecular geometry from the expected geometry based on the number of electron pairs.

Hence, owing to one lone pair present, the observed molecular geometry is bent.

6 0

2 years ago