All categories

3 years ago

How many elements have been discovered? A. 110 B. less than 110 C. more than 110

Chemistry

2 answers:

riadik2000 [5.3K]3 years ago

8 0

There are 115 known elements as of today (Feb. 13, 2016)

so, 'C' is the correct answer

Ivenika [448]3 years ago

6 0

C. more than 110. We have 115 elements known for Feb 2016.

You might be interested in

A solution is prepared by dissolving 150. grams of NaCl in 500 milliliters of water. What is the

Morgarella [4.7K]

Answer above should be correct!

5 0

3 years ago

Read 2 more answers

For every action there is an equal and opposite reaction is known as? *

wolverine [178]

Answer:

Newton's third law

3 0

3 years ago

Read 2 more answers

Solid aluminum (AI) and oxygen (O_2) gas react to form solid aluminum oxide (Al_2O_3). Suppose you have 7.0 mol of Al and 9.0 mo

Nimfa-mama [501]

Answer:

There will be formed 3.5 moles of Al2O3 ( 356.9 grams)

Explanation:

Step 1: Data given

Numbers of Al = 7.0 mol

Numbers of mol O2 = O2

Molar mass of Al = 26.98 g/mol

Molar mass of O2 = 32 g/mol

Step 2: The balanced equation

4Al(s) + 3O2(g) → 2Al2O3(s)

Step 3: Calculate limiting reactant

For 4 moles Al we need 3 moles O2 to produce 2 moles Al2O3

Al is the limiting reactant, it will be consumed completely (7 moles).

O2 is in excess. There will react 3/4 * 7 = 5.25 moles

There will remain 9-5.25 = 3.75 moles

Step 4: Calculate moles Al2O3

For 4 moles Al we'll have 2moles Al2O3

For 7.0 moles of Al we'll have 3.5 moles of Al2O3 produced

Step 5: Calculate mass of Al2O3

Mass Al2O3 = moles Al2O3 * molar mass Al2O3

Mass Al2O3 = 3.5 moles* 101.96 g/mol

Mass Al2O3 = 356.9 grams

There will be formed 3.5 moles of Al2O3 ( 356.9 grams)

3 0

3 years ago

The worst feeling is when you are hurting so badly inside but not a single tear comes out.

guapka [62]

Answer:

chemistry wow

Explanation:

8 0

3 years ago

If 42 grams of carbon and 52 grams of oxygen are used, how many grams of CO2 will be produced (Hint: find the

zavuch27 [327]

Answer:

71.5g

Explanation:

The reaction equation is given as:

C + O₂ → CO₂

Mass of C = 42g

Mass of O₂ = 52g

Unknown:

Mass of CO₂ produced = ?

Solution

Now to solve this problem, we have to find limiting reactant which is the one given in short supply in this reaction.

The extent of the reaction is controlled by this reactant.

Find the number of moles of the given species;

Number of moles = $\frac{mass}{molar mass}$

Number of moles of C = $\frac{42}{12}$ = 3.5mol

Number of moles of O₂ = $\frac{52}{32}$ = 1.63mol

Now;

From the balanced reaction equation;

1 mole of C reacted with 1 mole of O₂

We see that C is in excess and O₂ is the limiting reactant.

1 mole of O₂ will produce 1 mole of CO₂

So; 1.63mole of O₂ will produce 1.63 mole of CO₂

Mass of CO₂ = number of moles x molar mass

Molar mass of CO₂ = 44g/mol

Mass of CO₂ = 1.63 x 44 = 71.5g

8 0

3 years ago