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mr_godi [17]
3 years ago
10

Humans have used rocks in the creation of tools and building materials true or flase

Chemistry
2 answers:
olga55 [171]3 years ago
8 0

Answer:

true

Explanation:

Anuta_ua [19.1K]3 years ago
4 0
True, if you would like an example look at Indian arrow heads or early architecture all use rocks.
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A sample of gas at 1.10 atm has a volume of 326 mL. What is the new volume if the pressure is changed to 1.90 atm?
Brut [27]

Answer

For this we use ideal gas equation which is:

P1V1 = P2V2

P1 = 1.10 atm

V1 = 326 ml

P2 = 1.90

V2 = ?

By rearranging the ideal gas equation:

V2 =  P1V1 ÷ P2

V2 = 1.10 × 326 ÷1.90

V2 = 358.6 ÷ 1.90

V2 = 188.7 ml

8 0
3 years ago
What volume of oxygen at STP is requieres for the complete combustion of 100.50 mL of C2H2
malfutka [58]

The volume of oxygen at STP required would be 252.0 mL.

<h3>Stoichiometic problem</h3>

The equation for the complete combustion of C2H2 is as below:

2C_2H_2 + 5O_2 --- > 4CO_2 + 2H_2O

The mole ratio of C2H2 to O2 is 2:5.

1 mole of a gas at STP is 22.4 L.

At STP, 100.50 mL of C2H2 will be:

                 100.50 x 1/22400 = 0.0045 mole

Equivalent mole of O2 according to the balanced equation = 5/2 x 0.0045 = 0.01125 moles

0.01125 moles of O2 at STP = 0.01125 x 22400 = 252.0 mL

Thus, 252.0 mL of O2 gas will be required at STP.

More on stoichiometric problems can be found here: brainly.com/question/14465605

#SPJ1

7 0
1 year ago
Dichlorine heptoxide (C1 2 0 7) is a
Setler [38]

Answer:

Identify the "given" information and what the problem is asking you to "find."

Given : Cl2O7

Find: % Composition (% Cl and %O)

List other known quantities.

Mass of Cl in 1 mol Cl2O7 , 2 Cl : 2 x 35.45 g = 70.90 g

Mass of O in 1 mol Cl2O7 , 7 O: 7 x 16.00 g = 112.00 g

Molar mass of Cl2O7 = 182.90 g/mol

8 0
2 years ago
Which of these reactions successfully models a nuclear fission reaction?
user100 [1]

Answer:

OPTION B

Explanation:

Nuclear "fission" is the breakdown of the nucleus of a radioactive element into two or more nuclei accompanied by the release of energy. I guess that pretty much explains it.

3 0
2 years ago
An element has an atomic number of 18 and an atomic mass of 40. The number of neutrons in the nucleus of an atom of this element
Vikentia [17]

Answer: 22 neutrons

Explanation: 40 is the mass number = atomic mass = total number of protons and neutrons in atomic nucleus

18 is the number of protons in the nucleus of this atom

Then 40 - 18 = 22 neutrons

and this is Argon

7 0
3 years ago
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