These are the questions

3) 1

4) 0.2

5) 2

6) 1

7) 0.2

Explanation:

3)

The molarity of a substance is defined as the number of moles of the substance divided by how many liters the solution is. NaOH has a molar mass of about 40 grams, meaning that 10 grams of it would be 0.25 moles. 0.25/0.25= a molarity of 1.

4)

CO2 has a molar mass of just about 44 grams, meaning that 44 grams of it would be about a mole. 5000mL of solution is 5 liters, meaning that the molarity of this solution would be 1/5=0.2.

5)

HF has a molar mass of about 20, meaning that 20 grams of it is about a mole. 1/0.5=2M.

6)

Calcium flouride has a molar mass of about 78 grams, meaning that 156 grams is about two moles. 2000mL is 2 liters, meaning that this has a molarity of 2/2=1.

7)

Glucose has a molar mass of about 180 grams, meaning that 360 grams of it would be about 2 moles. 2/10=0.2.

Hope this helps!

linda: 3 ; laura: 15

step-by-step explanation:

note that linda + laura's age is 18, and that linda is 12 years younger than her sister.

let "linda" = x , "laura" = y:

x + y = 18

x = y - 12

first, plug in y - 12 for x in the first equation:

(y - 12) + y = 18

simplify.

2y - 12 = 18

isolate the variable (y). note the equal sign, what you do to one side, you do to the other. do the opposite of pemdas. first add, then divide.

2y - 12 (+12) = 18 (+12)

2y = 18 + 12

2y = 30

(2y)/2 = (30)/2

y = 30/2

y = 15

next, plug in 15 for y in the second equation (the other equation would work too).

x = y - 12

x = (15) - 12

x = 3

linda's age is 3, laura's age is 15.

~

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.