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3 years ago

Please Help Thank You

Chemistry

2 answers:

Stells [14]3 years ago

7 0

Its gonna be to learn about history on earth

Nikitich [7]3 years ago

5 0

The first option is the correct answer. Fossils belong to dinosaurs that lived in B.C/A.D, which scientists study to learn about Earth's prehistoric times.

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Can you solve question 5 and 6 only

Yanka [14]

Answer:

oil floats on water because it is heavier than water

Salt is no longer visible after stirring as salt dissolves in water

by filtration

4 0

2 years ago

Someone who’s good with science this is for you btw I’ll brainlist and rate 5 star due today.

alekssr [168]

Answer:

Solid Osmium transition metal reacts with Oxygen gas to produce solid Osmium tetroxide.

Os(s) + 2O₂(g) -> OsO₄(s)

Explanation:

Osmium tetroxide is another way of writing Osmium (VIII) oxide.

Leaving powdered osmium exposed to air in a room will slowly create osmium tetroxide at room temperature.

Similarly, osmium tetroxide vapor will readily be released from a liquid solution at room temperature.

7 0

2 years ago

A gas occupies the volume of 215ml at 15C and 86.4kPa?

kherson [118]

Answer:

About 0.1738 liters

Explanation:

Using the formula PV=nRT, where p represents pressure in atmospheres, v represents volume in liters, n represents the number of moles of ideal gas, R represents the ideal gas constant, and T represents the temperature in kelvin, you can solve this problem. But first, you need to convert to the proper units. 215ml=0.215L, 86.4kPa is about 0.8527 atmospheres, and 15C is 288K. Plugging this into the equation, you get:

$0.8527\cdot 0.215=n \cdot 0.0821 \cdot 288\\n\approx 7.754 \cdot 10^{-3}$

Now that you know the number of moles of gas, you can plug back into the equation with STP conditions:

$1V=7.754 \cdot 10^{-3} \cdot 0.0821 \cdot 273\\V\approx 0.1738L$

Hope this helps!

3 0

3 years ago

URGENT!! Can someone please explain this to me?

djverab [1.8K]

Answer:

$CH _{4}+ 2O _{2} → CO _{2} + 2H _{2}O$

for the balanced equation

$from \: the \: equation \\ 1 \: mole \: of \: methane \: gives \: 1 \: mole \: of \: carbon \: dioxide \\ 7.4 \: moles \: of \: carbon \: dioxide \: will \: be \: given \: by \: (7.4 \times 1)moles \: of \: methane \\ = 7.4\: moles \: of \: methane \\ \\ since \: moles \: of \: oxygen \: double \: those \: of \: methane \\ moles \: of \: oxygen \: = 7.4\times 2 \\ = 14.8 \: moles \: of \: oxygen$

4 0

2 years ago

Which compound is made from metals and non metals

Grace [21]

It’s -> Ionic compound

3 0

2 years ago