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Diano4ka-milaya [45]
3 years ago
12

Help! please and thank youu

Chemistry
2 answers:
Alja [10]3 years ago
7 0
The answer is B! (4.152x10^3) hope this helped!! Have a good day :)
Evgesh-ka [11]3 years ago
6 0

Answer:

B) 4.152 x 10^5

Explanation:

Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the 10. If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.

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Calorimetry can be used to determine the specific heat capacity of an unknown substance.
Liula [17]

Answer:

TRUE

Explanation:

Main job of calorimeter is to measure energy changes or determine specific heat capacity of different substances. Specific heat is an intensive property (like density, color, etc.) that does not depend on the amount of a substance present. This allows substances to be identified using their specific heat. Thus, calorimeter comes very handy in determining the specfic heat of unknown substance.

4 0
3 years ago
Endorphins are generated in the body during exercise, which leads to better emotional health. Please select the best answer from
Lostsunrise [7]

Answer: Yes the statement is true.

Explanation: Endorphins are chemicals produced by the human bodies to relieve stress and pain.

They are produced mainly by brain and help to transmit electrical signals within nervous system, thus are called as neurotransmitters.

They are also called as "feel good chemicals" as they can act as pain relievers and happiness booster and thus lead to better emotional health.

7 0
4 years ago
Read 2 more answers
You measure 2.34 g of K2Cr2O7 into a volumetric flask. You dilute the K2Cr2O7 with water to a volume of 250 mL. It takes 35.7 mL
natta225 [31]

Answer:

0.191M of Na₂C₂O₄ is the concentration of the original Na₂C₂O₄ solution

Explanation:

The reaction of potassium dichromate, K₂Cr₂O₇ with sodium oxalate, Na₂C₂O₄ in the presence of acid H⁺ is:

K₂Cr₂O₇ + 3Na₂C₂O₄ + 14H⁺ → 2Cr³⁺ + 6CO₂ + 7H₂O + 6Na⁺ + 2K⁺

<em>Thus, 1 mole of K₂Cr₂O₇ reacts with 3 moles of Na₂C₂O₄</em>

Moles of 2.34g of K₂Cr₂O₇ (Molar mass: 294.185g/mol):

2.34g K₂Cr₂O₇ ₓ (1mol / 294.185g) = 7.954x10⁻³ moles K₂Cr₂O₇

In 250mL = 0.250L:

7.954x10⁻³ moles K₂Cr₂O₇ / 0.250L = 0.0318M K₂Cr₂O₇

Moles in 35.7mL = 0.0357L of this solution are:

0.0357L ₓ (0.0318mol / L) = <em>1.136x10⁻³ moles K₂Cr₂O</em>₇ in solution. As 1 mole of K₂Cr₂O₇ reacts with 3 moles of Na₂C₂O₄, to titrate the moles of K₂Cr₂O₇ in solution you need:

1.136x10⁻³ moles K₂Cr₂O₇ × (3 moles Na₂C₂O₄ / 1 mole K₂Cr₂O₇) =

<em>3.408x10⁻³ moles of Na₂C₂O₄</em>

In 17.8mL = 0.0178L:

3.408x10⁻³ moles of Na₂C₂O₄ / 0.0178L =

<h3>0.191M of Na₂C₂O₄ is the concentration of the original Na₂C₂O₄ solution</h3>

<em />

3 0
3 years ago
how many grams of water are produced when 15 grams of magnesium hydroxide are reacted with sulfuric acid​
Mila [183]
<h3>Answer:</h3>

9.26 g of water

<h3>Explanation:</h3>

We are given;

  • 15 grams of magnesium hydroxide;

Required to calculate the mass of water produced;

We will use the following steps;

<h3>Step 1: Write the balanced equation for the reaction</h3>

Magnesium hydroxide reacts with sulfuric acid to produce water and magnesium sulfate;

Therefore, the equation of the reaction is;

Mg(OH)₂(aq) + H₂SO₄(aq) → MgSO₄(aq) + 2H₂O(l)

<h3>Step 2: Determine the number of moles of Mg(OH)₂ used </h3>

Number of moles = Mass ÷ Molar mass

Molar mass of Mg(OH)₂ =58.320 g/mol

Therefore;

Moles of Mg(OH)₂ = 15 g ÷ 58.320 g/mol

                             = 0.257 moles

<h3>Step 3: Calculate the moles of water produced</h3>

From the equation 1 mole of Mg(OH)₂ reacts to produce 2 moles of water;

Therefore; Moles of water = moles of Mg(OH)₂ × 2

Moles of water = 0.257 moles × 2

                         = 0.514 moles

<h3>Step 4: Calculate the mass of water produced;</h3>

Mass = Moles × Molar mass

Molar mass of water = 18.02 g/mol

Therefore;

Mass of water = 0.514 moles × 18.02 g/mol

                        = 9.26 g

Therefore, 9.26 g of water will be produced

3 0
3 years ago
Which soil would be the best for growing plants?
Leokris [45]

Honestly, its based on your preference but the best recommended one would be loam. I use loam too, and it is really good for growing the plants.

:)

7 0
3 years ago
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