1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
masya89 [10]
3 years ago
14

Denise owns a car that runs on a mixture of gasoline and ethanol. She can buy fuels that have 85% ethanol or 25% ethanol. How mu

ch of each type of fuel should she buy if she wants to fill her 20-gallon tank with a mixture of fuel that contains 50% ethanol?
Chemistry
1 answer:
Hunter-Best [27]3 years ago
5 0
<span>85% ethanol | 25% ethanol | 50% ethanol
x | y | 20 gal

use x and y because you don;t know how much she needs.

0.85x | 0.25y | 20(0.5)

85% is 85/100 or 0.85, and you need that much of x, same goes for the 25% and 50% mixtures so now you can make up 2 equations
1) x + y = 20 2) 0.85x + 0.25y= 10 (you get 10 when you multiply 20 by 0.5) now you can solve for x or y using substitution.
first rewrite 1) in terms of x or y: x+ y= 20 ----> y= 20 - x now you can substitute 20- x for y in the second equation.. 0.85x + 0.25y= 10 0.85x + 0.25(20-x)= 10 distribute here..(0.25 * 20 and 0.25 * (-x) ) 0.85x + 5 - 0.25x = 10 combine like terms 0.6x +5 = 10 move the 5 over to the other side 0.6x= 10 -5 0.6x = 5 divide both sides by 0.6 x= 25/3 or 8.3 now you know the amount of x so you can substitue this back into the first equation to find y. 0.85x + 0.25y= 10 0.85(25/3) +0.25y= 10 85/12 + 0.25y= 10 0.25y = 10- 85/12 0.25y= 35/12 y= 35/3 or 11.6 you can check by putting these values into the euations: 1) x+ y= 20 25/3 + 35/3 =20 20= 20 good so far 2) 0.85x + 0.25y= 10 0.85(25/3) + 0.25(35/3)=10 10 = 10

so our values for x and y work
x= 25/3 and y= 35/3</span>
You might be interested in
Cân bằng phương trình Mg+HCl-&gt;MgCl2+H2 bằng phương pháp thăng bằng
nignag [31]

quá trình oxi hóa: Mg0 -> Mg2+ + 2e-

quá trình khử: 2H+ + 2e- -> H2 (cần 2 H+ để tạo 1 H2)

----> chỉ cần thêm 2 vào trước HCl (vì H+ là do HCl cung cấp)

----> Mg + 2HCl -> MgCl2 + H2

yay :)

8 0
2 years ago
A concentration cell is constructed by using the same half-reaction for both the cathode and anode. What is the value of standar
Akimi4 [234]

Solution :

A cell that is concentrated is constructed by the same half reaction for the anode as well as he cathode.

We know,

In a standard cell,

the reduction half cell reaction is :

$Ag^+(aq)+e^- \rightarrow Ag(s) E^0 = -0.80 \ V$

The oxidation half ell reaction :

$Ag(s) \rightarrow Ag^+(aq) + e^- \ E^0= +0.80 \ V$

Thus the complete reaction of the cell is :

$Ag^+(aq)+ Ag(s) \rightarrow Ag^+(aq)+Ag(s)$

$E^0 $ cell = $E_R - E_L = 0.00  \ \text{volts}$

7 0
2 years ago
What two factors determine the thermal energy in a substance
Eduardwww [97]
The answer to that is mass and chemical
7 0
3 years ago
A solution contains one or more of the following ions: Ag+, Ca2+, and Co2+. Lithium bromide is added to the solution and no prec
olchik [2.2K]
<h3>Answer:</h3>

#1. Ca²⁺

# 2. Ca²⁺(aq) + SO₃²⁻(aq) → CaSO₄(s)

#3. 3Ag⁺(aq) + PO₄³⁻(aq) → Ag₃PO₄(s)

<h3>Explanation:</h3>

The question above concerns solubility of salts or ions in water.

The solution given contains Ag+, Ca2+, and Co2+ ions.

  • In the first case, when Lithium bromide is added to the solution, there is no white precipitate formed.
  • In the second case, the addition of Lithium sulfate results in the formation of a precipitate because of the Ca²⁺ in the solution combined with the SO₃²⁻ from lithium sulfate to form an insoluble CaSO₄.
  • The net ionic equation for the reaction is;

Ca²⁺(aq) + SO₃²⁻(aq) → CaSO₄(s)

  • From the solubility rules, all sulfates are soluble except BaSO₄, CaSO₄, and PbSO₄.
  • In the third case, the addition of Lithium phosphate results in the formation of a precipitate because Ag⁺ ions in the solution combine with phosphate ions ( PO₄³⁻) from lithium phosphate to form an insoluble salt, Ag₃PO₄.
  • The net ionic equation for the reaction is;

3Ag⁺(aq) + PO₄³⁻(aq) → Ag₃PO₄(s)

  • According to solubility rules, all phosphates are insoluble in water except Na₃PO₄, K₃PO₄, and (NH₄)₃PO₄.
6 0
3 years ago
Số hợp chất tố đa của nguyên tố này với nguyên tố khác theo hóa trị của nó
SVETLANKA909090 [29]

Answer:

Carbon

Explanation:

Carbon

5 0
3 years ago
Other questions:
  • Determine the mass in grams of 7.20 mol of antimony(molar mass =121.76g<br>​
    14·1 answer
  • 3) Of the choices below, which of the following contains covalent bonds? A. PCl5 B. RbCl C. PbCl2 D. MoCl6
    8·1 answer
  • What family is the mineral lead in?
    11·1 answer
  • a student is studying the ways different elements are similar to one another diagrams of atoms from four different elements are
    7·1 answer
  • What is The atomic mass number of tin
    13·2 answers
  • When minerals break along straight lines or flat planes we call that __________.
    15·2 answers
  • Molecules condense when the temperature ______________.<br> A. increases<br> B. decreases
    5·2 answers
  • What type of intermolecular force exist between H2O and Br2
    6·1 answer
  • Is anyone good at chemistry if so Can someone help me please NO LINKS
    6·1 answer
  • The following is the reaction showing the complete neutralization of calcium hydroxide (a base) with phosphoric acid:
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!