Answer:
B: circulatory system
Explanation:
The circulatory system is made up of blood vessels that carry blood away from and towards the heart. Arteries carry blood away from the heart and veins carry blood back to the heart. The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide.
Answer:
D.
Explanation:
D is the correct answer because, in aqueous solution, solvent is water and solute (in this example carbon dioxide CO₂) is a substance dissolved in water. The amount of solute that can be dissolved in a solvent depends of chemical composition, temperature and pressure
Answer:
compound
Explanation:
A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atoms that are held together by chemical bonds. These bonds form as a result of the sharing or exchange of electrons among atoms.
Step 1 : Write balanced chemical equation.
CaF₂ can be converted to F₂ in 2 steps. The reactions are mentioned below.
I] 
II] 
The final balanced equation for this reaction can be written as

Step 2: Find moles of CaF₂ Using balanced equation
We have 1.12 mol F₂
The mole ratio of CaF₂ and F₂ is 1:1

Step 3 : Calculate molar mass of CaF2.
Molar mass of CaF₂ can be calculated by adding atomic masses of Ca and F
Molar mass of CaF₂ = Ca + 2 (F)
Molar mass of CaF₂ = 40.08 + 18.998 = 78.08 g
Step 4 : Find grams of CaF₂
Grams of CaF₂ = 
Grams of CaF₂ = 87.45 g
87.45 grams of CaF2 would be needed to produce 1.12 moles of F2.
Hey there!
We can tell from the information we are given that the sum of protons and neutrons is 13, there is 6 protons since it is a carbon atom, and there is no charge which means the number of protons is equal to the number of electrons.
6 + n = 13
n = 7
The number of protons is equal to the number of electrons, so there is 6 electrons.
The isotope 13C has 6 protons, 6 electrons, and 7 neutrons.
Hope this helps!