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andrezito [222]
2 years ago
9

A grain of sand weighs approximately 0.0102 grams. How many molecules of SiO2 are in a grain of sand? Assume that sand is 100% S

iO2.
Chemistry
2 answers:
Sindrei [870]2 years ago
8 0

Answer:

 0.5

Explanation:

frutty [35]2 years ago
8 0

mol = mass  : MM SiO₂

mol = 0.0102 : 60 g/mol = 0.00017

molecules = 0.00017 x 6.02 x 10²³ = 1.0234 x 10²⁰

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How much heat must be removed from 25.0g of steam at 118.0C in order to form ice at 15C
NemiM [27]

Answer:

-10778.95 J heat must be removed in order to form the ice at 15 °C.

Explanation:

Given data:

mass of steam = 25 g

Initial temperature = 118 °C

Final temperature = 15 °C

Heat released = ?

Solution:

Formula:

q = m . c . ΔT

we know that specific heat of water is 4.186 J/g.°C

ΔT = final temperature - initial temperature

ΔT = 15 °C - 118 °C

ΔT = -103 °C

now we will put the values in formula

q = m . c . ΔT

q = 25 g × 4.186 J/g.°C × -103 °C

q = -10778.95 J

so, -10778.95 J heat must be removed in order to form the ice at 15 °C.

3 0
3 years ago
All atoms of the same elements have the same what?
Flura [38]

Answer:

The same number of proteins in their nucleus.

4 0
3 years ago
Read 2 more answers
The two elements discovered by Marie Curie are _____ and _____. uranium curium radium polonium
denpristay [2]
Marie Curie discovered polonium and radium. Hope this helps:))) Please, mark Brainliest!
5 0
3 years ago
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What is the weight of a 90kg man standing on the moon, where gmoon = 1.64 m/s2?
Doss [256]

Answer:

The weigth of a 90kg man standing on the moon is <u><em>147.6 N (option C)</em></u>

Explanation:

Weight is called the action exerted by the force of gravity on the body.

The mass (amount of matter that a body contains) of an object will always be the same, regardless of where it is located. Instead, the weight of the object will vary according to the force of gravity acting on it.

The formula that allows you to calculate the weight of any body is:

W = m*g

where:

  • W = weight measured in N.
  • m = mass measured in kg.
  • g = acceleration of gravity measured in m/s². The acceleration of gravity g is the same for all objects that fall due to gravitational attraction, whatever their size or composition. For example, as an approximate value on Earth, g = 9.8 m/s².

In this case,  the mass m has a value of 90 kg and the gravity g has a value of 1.64 m/s², which is the value of the acceleration of gravity of the moon. Then:

W=90 kg* 1.64 m/s²

<u><em>W= 147.6 N</em></u>

Finally, <u><em>the weigth of a 90kg man standing on the moon is 147.6 N (option C)</em></u>

3 0
4 years ago
Calculate the amount of solute needed for 1000 ml of 15% sodium thiosulfate
maksim [4K]
15% =  15 grams of solute in 100 mL solution

15 g --------------- 100 mL
?? ------------------ 1000 mL

1000 x 15 / 100 = 

15000 / 100 => 150 g of solute

hope this helps!
7 0
4 years ago
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