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disa [49]
2 years ago
9

When a scientist conducts an investigation, which of the following is the first thing he or she should do?

Chemistry
2 answers:
Vinvika [58]2 years ago
6 0

The correct answer is C

Lelu [443]2 years ago
5 0
The correct answer is "B. Make a Hypothesis".
You might be interested in
Write a program that allows the user to enter a number of quarters, dimes, and nickels and then outputs the monetary value of th
miskamm [114]

Answer:

// Program is written in C++ Programming Language

// Comments are used for explanatory purpose

// Program Starts here

#include<iostream>

using namespace std;

int main ()

{

// Declare Variables

int quarter, dimes, nickel, cent;

// Enter values for each

cout<<"Quarter: ";

cin>>quarter;

cout<<"Dimes: ";

cin>>dimes;

cout<<"Nickels: ";

cin>>nickel;

/*

In the United States, these coins have the following values

Quarter = 25 cents

Done = 10 cents

Nickel = 5 cent

Total cent is calculated below

*/

cent = 25 * quarter + 10 * dimes + 5 * nickel;

// Print Total

cout<<"The coins are worth "<<cent<<" cents";

return 0;

}

4 0
3 years ago
Uranium-238 decays to Lead-206. Both Rock X and Rock Y initially had a ratio of 100%. Uranium-238 to 0% Lead-206. Today, Rock X
kati45 [8]

Answer:

Rock Y

Explanation:

The rock that is older shall be determined based on the number of half lives it has witnessed. A half life is simply the amount of time required for a sample to decay to half of its original mass.

Rock X

From 100% uranium, it decays to 50% uranium.  This means it went through just one half life.

Rock Y

From 100% uranium to 25% uranium

100 --> 50 (first half life)

50 --> 25 (second half life)

This means it wen through 2 half lives.

Rock Y is older than Rock X

3 0
2 years ago
Which of the following is true of electronegativity?
Kay [80]

Answer:

c) It describes the affinity an atom has for an electron.

Explanation:

C quite literally describes what electronegativity is, you can rule out most others by looking at periodic trends as attached below.

4 0
10 months ago
When octane (C8H18) is burned in the presence of oxygen, the yield of products (carbon dioxide and water) is 87%. What mass of c
ahrayia [7]

Answer:

14.5g of CO₂ are produced

Explanation:

The reaction of octane with oxygen is:

C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O

<em>Where 1 mole of octane (Molar mass: 114.23g/mol) reacts with 25/2 moles of O₂ (Molar mass 32g/mol) to produce 8 moles of CO₂ and 9 moles of water.</em>

When 21.0 g of octane is burned with 19.0 g of oxygen gas you need to find <em>limiting reactant </em>to find how many moles of products are formed:

Octane: 21.0g ₓ (1mol / 114.23g) = 0.184 moles octane

Oxygen: 19.0g ₓ (1 mol / 32g) = 0.594 moles oxygen

For a complete reaction of 0.184 moles of octane you will need:

0.184 moles C₈H₁₈ ₓ (25/2 moles O₂ / 1 mole C₈H₁₈) = <em>2.3 moles of oxygen</em>

As you have just 0.594 moles of oxygen, <em>Oxygen is limiting reactant.</em>

Based on chemical equation, 25/2 of O₂ produce 8 moles of CO₂, that means theoretical yield of CO₂ with 0.594 moles of O₂ is:

0.594 moles O₂ ₓ (8 moles CO₂ / 25/2 moles O₂) = 0.380 moles of CO₂

But, as yield of products is 87%, moles produced of CO₂ are:

0.380 moles of CO₂ ₓ 87% = 0.331 moles CO₂ are produced.

As molar mass of CO₂ is 44g/mol, mass of CO₂ in 0.331 moles is:

0.331 moles CO₂ ₓ (44g / mol) =

<h3>14.5g of CO₂ are produced</h3>
6 0
2 years ago
What is the velocity of a plane that traveled 3000 miles from New York to Los Angeles in 5.0 hours?
miss Akunina [59]

Answer:

600 mph

Explanation:

Just divide 3000 by 5.

3 0
3 years ago
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