Answer:
37.5 g NaCl
Explanation:
Step 1: Given data
- Concentration of NaCl: 15.0% m/m
- Mass of the solution: 250.0 g
Step 2: Calculate how many grams of NaCl are in 250.0 g of solution
The concentration of NaCl is 15.0% by mass, that is, there are 15.0 g of NaCl every 100 g of solution.
250.0 g Solution × 15.0 g NaCl/100 g Solution = 37.5 g NaCl
14. a. Acidic
15. b. Weaker
16. d. Dilute and weak
Explanation:
14. Which type of the solution is one with the pH of 3?
Solution with pH from 1 to 7 are acidic, equal to 7 is neutral and from 7 to 14 basic. The solution with the pH equal to 3 is <u>acidic</u>.
15. The smaller the value of the base dissociation constant (Kb), the <u>weaker</u> the base.
The dissociation reaction of a base (B) is:
B + H₂O → BH⁺ + OH⁻
Kb is defined as:
Kb = ( [BH⁺] × [OH⁻] ) / ( [B] × [H₂O] )
The potency of the base depends on the concentration of the hydroxide ion [OH⁻], so if the Kb ratio is small it means that the concentration of hydroxide ion is smaller so the base will be <u>weaker</u>.
16. A 0.39 M solution of an acid that ionizes only slightly in solution would be termed <u>dilute and weak</u>.
The acid is weak because is only slightly ionizing in solution. The therm diluted is a little bit arbitrarily because we ask yourself "diluted in respect with what"? I would characterize the acid to be diluted at a concentration of 1 M and concentrated at a concentration of 10 M.
Learn more about:
pH
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<span>Let's assume
that the oxygen gas has ideal gas behavior.
Then we can use ideal gas formula,
PV = nRT</span>
Where, P is the pressure of the gas (Pa), V is the volume of the gas
(m³), n is the number of moles of gas (mol), R is the universal gas
constant ( 8.314 J mol⁻¹ K⁻¹) and T is temperature in Kelvin.
<span>
P = 2.2 atm = 222915 Pa
V = 21 L = 21 x 10</span>⁻³ m³
n = ?
R = 8.314 J mol⁻¹ K⁻¹
<span>
T = 87 °C = 360 K
By substitution,
</span>222915 Pa x 21 x 10⁻³ m³ = n x 8.314 J mol⁻¹ K⁻<span>¹ x 360 K
n
= 1.56</span><span> mol</span>
<span>
Hence, 1.56 moles of the oxygen gas are </span><span>
left for you to breath.</span><span>
</span>
Halogens are a group of elements consisting of Fluorine, Chlorine, Bromine, Iodine and Astatine. In their ionic form, they have a superscript of -1, for example, chloride ion is Cl-1. These means that they readily accept one electron in order to achieve the Octet rule. The Octet rule states that each atom must contain 8 electrons in their valence shell for it to be stable. The most stable set of elements are the noble gases. Because they already fulfill the Octet rule, they no longer take part in reactions. Halogens are also very electronegative, meaning, they attract more electrons toward them. This is also a consequence of the Octet rule.
From the choices, the answers would be:
<span>they require only one electron to complete their outer shell
they have a high electronegativity</span>
Answer:
N2H4 + 2H2O2 ---->N2 + 4H2O
Explanation:
N=2 N=2
H=6 ->8 H=2 ->8
O=2 -> 4 O=1 -> 4
Add coefficients to hydrogen peroxide on the left and water on the right, so that there is an equal number of hydrogens and oxygens.
