Answer:
I cannot give you all the answer but I can help you to solve those.
Explanation:
The first question:
How many grams are there in 7.5×
molecules of 
?
So we need to find the molecular mass first, use your periodic table,
And then we can find out 2+32+16×4=98 g/mol
Then, we need to find how many moles, by using Avogadro's constant:
Avogadro's constant: 1 mole = 6.02×
∴
=1.25 mol(2d.p.)
Lastly, find the grams using the formula 
m=Mn
m=1.25*98
m=122.5g
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In conclusion, use those formula to help you:
(which M = molecular mass(atomic mass) m=mass of the substance and n = moles)
Avogadro's constant: 
<u>Answer:</u> The final temperature of the mixture is 51.49°C
<u>Explanation:</u>
When two samples of water are mixed, the heat released by the water at high temperature will be equal to the amount of heat absorbed by water at low temperature
The equation used to calculate heat released or absorbed follows:
![m_1\times c\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)]](https://tex.z-dn.net/?f=m_1%5Ctimes%20c%5Ctimes%20%28T_%7Bfinal%7D-T_1%29%3D-%5Bm_2%5Ctimes%20c_2%5Ctimes%20%28T_%7Bfinal%7D-T_2%29%5D)
......(1)
where,
q = heat absorbed or released
= mass of water at high temperature = 140 g (Density of water = 1.00 g/mL)
= mass of water at low temperature = 230 g
= final temperature = ?°C
= initial temperature of water at high temperature = 95.00°C
= initial temperature of water at low temperature = 25.00°C
c = specific heat of water= 4.186 J/g°C
Putting values in equation 1, we get:
![140\times 4.186\times (T_{final}-95)=-[230\times 4.186\times (T_{final}-25)]](https://tex.z-dn.net/?f=140%5Ctimes%204.186%5Ctimes%20%28T_%7Bfinal%7D-95%29%3D-%5B230%5Ctimes%204.186%5Ctimes%20%28T_%7Bfinal%7D-25%29%5D)
Hence, the final temperature of the mixture is 51.49°C
Answer:
the attractive forces keep the particles together tightly enough so that the particles do not move past each other.
Explanation:
In the solid the particles vibrate in place.
Atoms are electrically neutral because they have equal numbers of protons (positively charged) and electrons (negatively charged).
Answer:
5.4 tonnes.
Explanation:
The first step is to find the molar mass of Al2O3. Aluminum has a molar mass of about 27 and oxygen has a molar mass of about 16, so 2(27)+3(16)= 102g/mol=0.102kg/mol. 10200kg/0.102kg/mol=100,000 moles of Al2O3 in 10.2 tonnes. Multiplying this by the molar mass of the two aluminums, you get a total of 54*100,000=5400000g=5400kg=5.4 tonnes. Hope this helps!
