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3 years ago

Susan needs to simplify the expression shown below what should be her first step

Chemistry

1 answer:

Digiron [165]3 years ago

5 0

Susan should follow PEMDAS,

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction,

So, the first step should be, to solve the equation in the parentheses.

I hope this helps!

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For a certain experiment, a student requires 100 milliliters of a solution that is 8% HCl (hydrochloric acid). The storeroom has

exis [7]

Answer:

70 mL of 5% HCl and 30 mL of 15% HCl

Explanation:

We will designate x to be the fraction of the final solution that is composed of 5% HCl, and y to be the fraction of the final solution that is composed of 15% HCl. Since the percentage of the final solution is 8%, we can write the following expression:

5x + 15y = 8

Since x and y are fractions of a total, they must equal one:

x + y = 1

This is a system of two equations with two unknowns. We will proceed to solve for x. First, an expression for y is found:

y = 1 - x

This expression is substituted into the first equation and we solve for x.

5x + 15(1 - x) = 8

5x+ 15 - 15x = 8

-10x = -7

x = 7/10 = 0.7

We then calculate the value of y:

y = 1 - x = 1 - 0.7 = 0.3

Thus 0.7 of the 100 mL will be the 5% HCl solution, so the volume of 5% HCl we need is:

(100 mL)(0.7) = 70 mL

Similarly, the volume of 15% HCl we need is:

(100 mL)(0.3) = 30 mL

3 0

3 years ago

Part 1: Name the type of chemical reaction that occurs when calcium hydroxide (Ca(OH)2) reacts with nitric acid (HNO3).

liberstina [14]

<u>Answer:</u>

<u>For 1:</u> Neutralization reaction

<u>For 2: </u>Zinc is more reactive than lead and less reactive than calcium.

<u>Explanation:</u>

<u>For (1):</u>

When a base reacts with an acid to form a salt and water molecule, it is known as a neutralization reaction. The general equation follows:

$HX+BOH\rightarrow BX+H_2O$

The chemical equation for the reaction of calcium hydroxide and nitric acid follows:

$Ca(OH)_2(aq)+2HNO_3(aq)\rightarrow Ca(NO_3)_2(aq)+2H_2O(l)$

<u>For (2):</u>

A single displacement reaction is defined as the reaction in which a more reactive metal displaces a less reactive metal from its salt solution. The general chemical equation follows:

$A+BX\rightarrow AX+B$

where,

Metal A is more reactive than metal B

The reactivity of metals is judged by the reactivity series where a metal lying above in the series is more reactive than the metal lying below it.

From the reactivity series below,

Zinc lies above in the series than lead thus is more reactive and will easily replace lead from its aqueous solution.

While zinc lies below in the series than calcium thus is less reactive and will not easily replace calcium from its aqueous solution.

$Zn(s)+Pb(NO_3)_2(aq)\rightarrow Zn(NO_3)_2(aq)+Pb(s)$

$Zn(s)+CaCl_2(aq)\rightarrow \text{No reaction}$

5 0

3 years ago

How is nuclear energy generated?

balandron [24]

Nuclear power plants heat water to produce steam. The steam is used to spin large turbines that generate electricity. ... In nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Fission takes place inside the reactor of a nuclear power plant.

3 0

2 years ago

Read 2 more answers

Please show all work:

Tom [10]

If 40.0 grams of magnesium is reacted with an excess of nitric acid. 3.3 g of hydrogen gas will be produced.

<h3>What is Stoichiometry ?</h3>

Stoichiometry helps us use the balanced chemical equation to measure quantitative relationships and it is to calculate the amounts of products and reactants that are given in a reaction.

<h3>What is Balanced Chemical Equation ?</h3>

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

Now we have to write the balanced equation

Mg + 2HNO₃ → Mg(NO₃)₂ + H₂

According to Stoichiometry

$40.9\ \text{g Mg} \times \frac{1\ \text{mol Mg}}{24.31\ \text{g Mg}} \times \frac{1\ \text{mol}\ H_2}{1\ \text{mol Mg}} \times \frac{2.02\ g\ H_2}{1\ \text{mol}\ H_2}$

= 3.3 g H₂

Thus from the above conclusion we can say that If 40.0 grams of magnesium is reacted with an excess of nitric acid. 3.3 g of hydrogen gas will be produced.

Learn more about the Stoichiometry here: brainly.com/question/16060223

#SPJ1

8 0

1 year ago

Chemistrys forerunners

oksian1 [2.3K]

Answer:

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4 0

3 years ago