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KiRa [710]
3 years ago
6

The sum of two number is 50,and their difference is 30.find the sum​

Chemistry
2 answers:
Alexeev081 [22]3 years ago
5 0

Answer:

40 and 10

Explanation:

kompoz [17]3 years ago
4 0

Answer:

40 and 10

Explanation:

40 plus 10 is 50 40 minus 10 is 30

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if matter is made of many tiny particles, why does it seem to be continuous? Why doesn’t water seem to behave like sand?
valkas [14]

Answer:

Explanation:

if matter is made of many tiny particles, why does it seem to be continuous? Why doesn’t water seem to behave like sand?

Water and some other molecules exhibit a property know as hydrogen bonding.  A hydrogen atom in one molecule of water is attracted to the oxygen in a neighboring molecules of water.'

The force of this attraction is less than a standard chemical attractive force, but it is real and measurable.

When billions and trillions of water molecules are held together by this force, the small amount of molecule to molecule force is added up to a tremendous force.  That is why even though sulfur is below oxygen on the periodic table, hydrogen sulfide is a gas while hydrogen oxide is a liquid at room temperature.

Hydrogen bonding explains the unique properties of ice, liquid water and steam,We all know water exists in several forms such as solid, liquid and ice. Water boils at 100  C and freezes at 32  F, right? Am I correct? Let us look at some of the chemistry behind forms of water.  

The strong polar bond between water molecules creates water cohesion.

As they are cooled, aggregates of most other substances increase monotonically in density becoming progressively heavier -- the colder they are, the more tightly packed their molecules become. But water possesses a peculiar physical feature: ice expands, so it is lighter than liquid water (i. e., ice floats). When water trapped in rock crevices freezes, it breaks rocks (and pipes).

 

Water is vital to all known life forms, that is, all those on planet Earth. It is so integral to life as we know it that many biologists cannot even envision life without water (although that might be possible). Indeed, the physical properties of water dictate critical thermal limits for living systems.

In one sci-fi story, an alien refers to humans as "ugly bags of mostly water" -- our bodies are about 60-70% water, depending upon how dehydrated we are at any given time. Humans use massive amounts of freshwater to drink, cook, bathe, flush toilets, do laundry, fill swimming pools, irrigate yards and gardens, run flowing fountains, and for recreation. Precious clean water is often wasted, such as when people leave tap water running while washing their hands or brushing their teeth. The personal water consumption of an average American is about 200 gallons per day, but when industrial and energy usage is added in, per capita freshwater usage is more than 2000 gallons/day. People in third world countries use much less water, of course.

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7 0
2 years ago
To what temperature must a balloon, initially at 25°c and 2.00 l, be heated in order to have a volume of 6.00 l? question 8 opti
cluponka [151]
<span>a.655 k not 100 percent on this but try it. You will use 273.15 and add your Celcius temp to get it in Kelvin
</span>
5 0
3 years ago
Read 2 more answers
The atomic mass of oxygen is 15.999 amu whatbdoes the value equal
sweet-ann [11.9K]

Answer:

The sum of the protons and neutrons.

Explanation:

protons + neutrons = atomic mass

7 0
2 years ago
South Florida is surrounded by salt water. The need for fresh
Lady bird [3.3K]

Answer:

Aquifer

Explanation:

Instead of snowcapped mountains that store water in advance of warmer temperatures, most of our drinking water comes from underground "mountains" of porous materials called aquifers which are replenished by rain. The Biscayne Aquifer is South Florida's lower east coast's primary source of fresh water.

3 0
3 years ago
If 4.0 g of helium gas occupies a volume of 22.4 L at 0 o C and a pressure of 1.0 atm, what volume does 3.0 g of He occupy under
WINSTONCH [101]

Answer:

the volume occupied by 3.0 g of the gas is 16.8 L.

Explanation:

Given;

initial reacting mass of the helium gas, m₁ = 4.0 g

volume occupied by the helium gas, V = 22.4 L

pressure of the gas, P = 1 .0 atm

temperature of the gas, T = 0⁰C = 273 K

atomic mass of helium gas, M = 4.0 g/mol

initial number of moles of the gas is calculated as follows;

n_1 = \frac{m_1}{M} \\\\n_1 = \frac{4}{4} = 1

The number of moles of the gas when the reacting mass is 3.0 g;

m₂ = 3.0 g

n_2 = \frac{m_2}{M} \\\\n_2 = \frac{3}{4} \\\\n_2 = 0.75 \ mol

The volume of the gas at 0.75 mol is determined using ideal gas law;

PV = nRT

PV = nRT\\\\\frac{V}{n} = \frac{RT}{P} \\\\since, \ \frac{RT}{P} \ is \ constant,\  then;\\\frac{V_1}{n_1} = \frac{V_2}{n_2} \\\\V_2 = \frac{V_1n_2}{n_1} \\\\V_2 = \frac{22.4 \times 0.75}{1} \\\\V_2 = 16.8 \ L

Therefore, the volume occupied by 3.0 g of the gas is 16.8 L.

4 0
3 years ago
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