The mass of 254 mL of water is 254 g. Since the density of water is 1g/mL, we can simply multiply the density 1g/mL by 254 mL of water and get 254 g as our answer. Since mL is in the numerator and denominator, mL cancels out and we are left with g only.
Answer: It becomes the uncombined element in the product.
Explanation:
The reaction between Zn and HCl is a single displacement reaction according to equation below
Zn + 2HCl —> ZnCl2 + H2
Zn displaces H2 from acid and in the product, hydrogen became the uncombined element.
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
<em>M CaCl₂: 40+(35,5×2) = 111 g/mol</em>
6,02·10²³ molecules ---------- 111g
X molecules --------------------- 75,9g
X = (75,9×<span>6,02·10²³)/111
X = <u>4,116</u></span><span><u>·10²³</u> molecules of CaCl</span>₂
:)
Answer:
8.88 x 10⁻² M/s
Explanation:
The rate of reaction for:
NO(g) + Cl₂ (g) ⇒ 2NOCl(g)
is rate = -ΔNO/Δt = -ΔCl2/Δt = 1/2 ΔNOCl/Δt
so ΔNOCl/Δt = 2 ΔCl2/Δt = 2 x 4.44 × 10⁻² M/s = 8.88 x 10⁻² M/s
In general given a reaction
aA + bB ⇒ cC + dD
rate = -1/a ΔA/Δt = -1/b ΔB/Δt = 1/c ΔC/Δt = 1/d ΔD/Δt
