An investigation into an unknown object in space resulted in the following observations:

A solution is prepared by adding 100 ml of 0.2 m hydrochloric acid to 100 ml of 0.4 m sodium formate. is this a buffer solution,

Firdavs [7]

Becoing itsodim fromate t will have pb of 67

5 0

3 years ago

Which of the following are isotopes, choose all that apply.

Juliette [100K]

Answer:

Element X with atomic number 10 and atomic mass 21

Element Z with atomic number 10 and atomic mass 22

Explanation:

Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.

Isotopes of an element have the same electronic configuration.
They share the same chemical properties
They only differ in their masses.

So, Element X and Z with atomic number 10 which is their number of electrons are isotopes. Their mass number, 21 and 22 differs.

4 0

3 years ago

Mike, Jackie, Jeremy, and Niki were widely known to the be the fastest fifth graders at Robinson Elementary School. They wanted

riadik2000 [5.3K]

Jackie is the fastest student. (Option A)

Explanation:

From the table it was understood that their speeds are given in meter per second, that is how many meters they run in one second. It was again shown that Jackie's race speed is 5.3 meter per second and all the other three namely Jeremy's speed is 3.9 meter per second, Mike's speed is 4.1 meter per second and finally Niki's speed is 3.8 meter per second.
So, by comparing with others Jackie is the fastest runner in that race.

8 0

3 years ago

How many moles are in 1.51x10^26 atoms of xenon (Xe)? Please and thank you :)!!

RoseWind [281]

<h3>Answer:</h3>

251 mol Xe

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

<u>Atomic Structure</u>

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<u>Stoichiometry</u>

Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[Given] 1.51 × 10²⁶ atoms Xe

[Solve] moles Xe

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

[DA] Set up: $\displaystyle 1.51 \cdot 10^{26} \ atoms \ Xe(\frac{1 \ mol \ Xe}{6.022 \cdot 10^{23} \ atoms \ Xe})$
[DA] Multiply/Divide [Cancel out units]: $\displaystyle 250.747 \ mol \ Xe$

<u>Step 4: Check</u>

<em>Follow sig fig rule and round. We are given 3 sig figs.</em>

250.747 mol Xe ≈ 251 mol Xe

3 0

3 years ago

Ammonia and oxygen react to produce nitric oxide and water. Which of the following chemical equations describes this reaction an

aksik [14]

Answer:

Option B. 4NH3(g) + 5O2(g) —> 4NO(g) + 6H2O(g)

Explanation:

The reaction between ammonia, NH3 and oxygen, O2, will produce nitric oxide and water as shown below:

NH3(g) + O2(g) —> NO(g) + H2O(g)

Now, let us balance the equation.

This is illustrated below:

NH3(g) + O2(g) —> NO(g) + H2O(g)

There are 3 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 4 in front of NH3 and 6 in front of H2O as shown below:

4NH3(g) + O2(g) —> NO(g) + 6H2O(g)

There are 4 atoms of N on the left side and 1 atom on the right side. It can be balance by putting 4 in front of NO as shown below:

4NH3(g) + O2(g) —> 4NO(g) + 6H2O(g)

Now, the are 2 atoms of O on the left side and a total of 10 atoms on the right side. It can be balance by putting 5 in front of O2 as shown below:

4NH3(g) + 5O2(g) —> 4NO(g) + 6H2O(g)

Now, we can see that the equation is balanced.

Therefore, option B gives the balanced chemical equation for the reaction.

5 0

3 years ago