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Elis [28]
3 years ago
11

I NEED HELP RIGHT NOW

Chemistry
1 answer:
PolarNik [594]3 years ago
7 0
There are a total of 4 elements
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A rectangle has a volume of 395cm3. It has a mass of 147g. What is its density? *
LekaFEV [45]

The density of a rectangle : ρ = 0.372 g/cm³

<h3>Further explanation</h3>

Given

The volume of rectangle : 395 cm³

Mass : 147 g

Required

The density

Solution

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

Density formula:  

\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}

ρ = density  

m = mass  

v = volume

Input the value :

ρ = 147 g : 395 cm³

ρ = 0.372 g/cm³

6 0
3 years ago
Mary starts from her house, walks 80 meters south, and stops to chat with her aunt on the sidewalk. After chatting for a few min
Olenka [21]
(80+125+45) / 10 = 250/10 =25
25 meters per minute= 0.41 meters/second

the direction and stopping time is irrelevant to the problem.
6 0
3 years ago
Identify the following changes as physical or chemical.
andrezito [222]

Answer:

physical

Explanation:

5 0
3 years ago
What aqueous solution has the highest boiling point at standard pressure? A) 1.0 M KCl(aq) B) 1.0 M CaCl2(aq) C) 2.0 M KCl(aq) D
Lapatulllka [165]
The increase in the boiling point of a solvent is a colligative property.


That means that the increase in the boling point will be related to the number of particles (molecules or ions) present in the solution.


The higher the number of particles (molecules or ions) the higher the increase in the boiling point.


All the aqueous solutions presented are electrolytes, i.e. the solutes are ionic compounds.


Then, you have to compare the number of ions that you have in each solution.


A) 1.0 M KCl ---> 1.0 M K+     +      1.0 MCl-    = 2 moles of particles / liter


B) 1.0 M CaCl2 --> 1.0M Ca(2+)      +      1.0M * 2 Cl (-)    = 3 moles of particle / liter


C) 2.0M KCl ---> 2.0 M K+      +      2.0 M Cl-  = 4 moles of particle / liter


D) 2.0 M CaCl2 ----> 2.0 M Ca (2+)      + 2.0M * 2 Cl (-)  = 6 moles of particle / liter.


Then, the solution 2.0M CaCl2(aq) has the highest increase in the boiling point.


Answer: option D) 2.0 M Ca Cl2(aq)
5 0
3 years ago
Neptunium-237 undergoes a series of α-particle and β-particle productions to end up as thallium-205. How many α particles and β
Fantom [35]
<h3>Answer:</h3>

8 alpha particles

4 beta particles

<h3>Explanation:</h3>

<u>We are given;</u>

  • Neptunium-237
  • Thallium-205
  • Neptunium-237 undergoes beta and alpha decay to form Thallium-205.

We are required to determine the number of beta and alpha particles produced to complete the decay series.

  • We need to know that when a radioisotope emits an alpha particle the mass number reduces by 4 while the atomic number decreases by 2.
  • When a beta particle is emitted the mass number of the radioisotope increases by 1 while the atomic number remains the same.

In this case;

Neptunium-237 has an atomic number 93, while,

Thallium-205 has an atomic number 81.

Therefore;

²³⁷₉₃Np → x⁴₂He + y⁰₋₁e + ²⁰⁵₈₁Ti

We can get x and y

237 = 4x + y(0) + 205

237-205 = 4x

4x = 32

 x = 8

On the other hand;

93 = 2x + (-y) + 81

but x = 8

93 = 16 -y + 81

y = 4

Therefore, the complete decay equation is;

²³⁷₉₃Np → 8⁴₂He + 4⁰₋₁e + ²⁰⁵₈₁Ti

Thus, Neptunium-237 emits 8 alpha particles and 4 beta particles to become Thallium-205.

5 0
2 years ago
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