<span>Which of the following are indicators of a chemical change? Select all that apply.
</span>
These are the answers:
<span>color change
temperature change
precipitate formation
gas formation
Hope this helps.
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Answer:
Nucleus
Explanation:
Nucleus is your blueprint for the cell. It has all the directions packaged in tiny DNA molecules. The nucleus of a cell is an organelle that stores the cell's hereditary material, or DNA, and it coordinates the cell's activities, which include growth, intermediary metabolism, protein synthesis, and reproduction.
Answer:

Explanation:
Hello!
In this case, when two substances at different temperature are put in contact and an equilibrium temperature is attained, we can evidence that the heat lost by the hot substance (metal) is gained by the cold substance (water) and we can write:

Which can be also written as:

Thus, since we need the specific heat of the metal, we solve for it as shown below:

Best regards.
Answer:
The student's speed is 60 mph.
Explanation:
All you have to do is divide: 260/4 = 60 mph.
Explanation:
In order to go from mass of magnesium to atoms of magnesium, we have to do two things:
Convert mass of Mg to moles of Mg using the molar mass of Mg as a conversion factor
Convert moles of Mg to atoms of Mg using Avogadro's number (6.02×1023) as a conversion factor
Step 1:
Before we start, I should note that the molar mass of Mg is 24.31gmol. We can go from mass to moles using dimensional analysis. The key to dimensional analysis is understanding that the units that you don't need any more cancel out, leaving the units that are desired:
48.60g
×1mol24.31g
=2.00mol
Step 2:
We'll use this relationship:
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Using the moles of Mg that we just obtained, we can use Avogrado's number to perform dimensional analysis in order to cancel out units of mol to end up with atoms of Mg:
2.00mol
×6.02×1023atoms1mol
=1.204×1024atoms
Thus, 48.60g of Mg is equivalent to 1.204×1024atoms
Hope this helped :)