Answer:

Explanation:
Density is found by dividing the mass by the volume.

The mass of the liquid is 12.7 grams.
We know that 15 mL of this liquid was added to a 50 mL graduated cylinder. Therefore, the volume is 15 mL. The 50 mL is not relevant, it only tells us about the graduated cylinder.

Substitute the values into the formula.

Divide.

Round to the nearest hundredth. The 6 in the tenth place tells us to round the 4 to a 5.

The density of the liquid is about 0.85 grams per milliliter and choice A is correct.
Answer:

Explanation:
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In this case, according to the given chemical reaction for this problem about stoichiometry:

Whereas there is a 3:2 mole ratio of oxygen (molar mass = 32.0 g/mol) to iron (III) oxide (molar mass = 159.69 g/mol) and therefore, the correct stoichiometric setup is:

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Answer:
It's D. On the surface of the solid.
Explanation:
If the reactant is a solid, the surface area of the solid will impact how fast the reaction goes. This is because the two types of molecule can only bump into each other at the liquid solid interface, i.e. on the surface of the solid. So the larger the surface area of the solid, the faster the reaction will be.
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Answer:
14 mol O₂
Explanation:
The reaction between CO and O₂ is the following:
CO + O₂ → CO₂
We balance the equation with a coefficient 2 in CO and CO₂ to obtain the same number of O atoms:
2CO + O₂ → 2CO₂
As we can see from the balanced equation, 1 mol of O₂ is required to react with 2 moles of CO. Thus, the conversion factor is 1 mol of O₂/2 mol CO. We multiply the moles of CO by the conversion factor to calculate the moles of O₂ that are required:
28 mol CO x 1 mol of O₂/2 mol CO = 14 mol O₂