How many grams of calcium are in 2.65 g of CaCO3?

HELP ILL GIVE U FREE POINTS AND BRAINLEST !! Observe the plate boundary shown here. What type of plate boundary is this? Many ge

Studentka2010 [4]

The answer is B.
You can rule C out because divergent means moving away. Rule out A because there is an oceanic and continental plate, not 2 of the same type. Rule D out for the same reason.

3 0

3 years ago

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A researcher recorder that a chemical reaction require 2.90 gal water and raised the temperature of the reaction vessel by 57°F.

Ivan

Answer:

10.875L

Explanation:

The problem here is a simple conversion. The conversion is from gal to liters Liter is a SI unit for recording volume as stated in the problem.

Given that:

1 gallon of water = 3.75L

2.90 gallon will be 2.9 x 3.75; 10.875L

4 0

3 years ago

The half-life of radium-226 is 1590 years. (a) A sample of radium-226 has a mass of 50 mg. Find a formula for the mass of the sa

Maksim231197 [3]

Answer:

Explanation:

a )

m = m₀ $e^{-\lambda t$

m is mass after time t . original mass is m₀ , λ is disintegration constant

λ = .693 / half life

= .693 / 1590

= .0004358

m = m₀ $e^{- 0.0004358 t}$

b )

m = 50 x $e^{-.0004358\times 500}$

= 40.21 mg .

c )

40 = 50 $e^{-.0004358t$

.8 = $e^{-.0004358t$

$e^{.0004358t$ = 1.25

.0004358 t = .22314

t = 512 years .

4 0

3 years ago

The decomposition of carbon disulfide to carbon monosulfide and sulfur is first order with k=2.8 ×10^-7 at 1000°C .What is the h

RoseWind [281]

Answer:

2.5×10⁶ s

Explanation:

From the question given above, the following data were obtained:

Rate constant (K) = 2.8×10¯⁷ s¯¹

Half-life (t½) =?

The half-life of a first order reaction is given by:

Half-life (t½) = 0.693 / Rate constant (K)

t½ = 0.693 / K

With the above formula, we can obtain the half-life of the reaction as follow:

Rate constant (K) = 2.8×10¯⁷ s¯¹

Half-life (t½) =?

t½ = 0.693 / K

t½ = 0.693 / 2.8×10¯⁷

t½ = 2.5×10⁶ s

Therefore, the half-life of the reaction is 2.5×10⁶ s

6 0

3 years ago

Calculate the hydronium ion concentration in an aqueous solution with a poh of 4.33 at 25°c.

Jlenok [28]

Taking into account the definition of pH and pOH, the hydronium ion concentration in an aqueous solution with a pOH of 4.33 at 25°c is 2.138×10⁻¹⁰ M.

<h3>Definition of pH</h3>

pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or hydronium ion H₃O⁺:

pH= - log [H⁺]= - log [H₃O⁺]

<h3>Definition of pOH</h3>

Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:

pOH= - log [OH⁻]

<h3>Relationship between pH and pOH</h3>

The following relationship can be established between pH and pOH:

pOH + pH= 14

<h3>Concentration of hydronium ions</h3>

Being pOH= 4.33, pH is calculated as:

pH + 4.33= 14

pH= 14 - 4.33

Replacing in the definition of pH the concentration of hydronium ions is obtained:

- log [H₃O⁺]= 9.67

Solving:

[H₃O⁺]= 10⁻⁹ ⁶⁷

Finally, the hydronium ion concentration in an aqueous solution with a pOH of 4.33 at 25°c is 2.138×10⁻¹⁰ M.

Learn more about pH and pOH:

brainly.com/question/16032912

brainly.com/question/13557815

#SPJ1

4 0

2 years ago