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4 years ago

Scientist discover that stars in the universe are mostly composed of which elements?

Chemistry

1 answer:

konstantin123 [22]4 years ago

3 0

Scientists discovered that starts in the universe are comprised mostly of hydrogen and helium, I believe.

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The atomic mass of hydrogen-1 is 1.008 and the atomic mass of helium-4 is 4.003. Find the difference in grams between 4 moles of

CaHeK987 [17]

4 moles of hydrogen = 4 * 1.008 = 4.032 grams

1 mole of helium = 4.003 grams

Difference is 4.032 - 4.003

= 0.029 g

7 0

3 years ago

Read 2 more answers

What is the specific heat capacity of an unknown metal if 75.00 g of the metal absorbs 418.6J of heat and the temperature rises

EleoNora [17]

Answer:

The specific heat capacity of the unknown metal is 0.223 $\frac{J}{g*C}$

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

There is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Q= 418.6 J
c= ?
m= 75 g
ΔT= 25 C

Replacing:

418.6 J= c* 75 g* 25 C

Solving:

$c=\frac{418.6 J}{75 g*25 C}$

c= 0.223 $\frac{J}{g*C}$

The specific heat capacity of the unknown metal is 0.223 $\frac{J}{g*C}$

3 0

2 years ago

What is the volume of 3.89 grams of helium gas?

lukranit [14]

Answer: There are 971.77 millimoles in 3.89 grams of Helium

Explanation:

i think its right im not really sure

7 0

3 years ago

Do protons determine isotopes

Bezzdna [24]

Answer:

Explanation:

Protons determine the type of element it is which the number of protons.

Isotopes are determined by the same elements with the same amount of protons, but different number of neutrons.

5 0

3 years ago

Why is baking soda an ionic bond

Kaylis [27]

Because it is made up of sodium, a metal, and carbon, a nonmetal.

Hope I helped ♡

6 0

4 years ago

Read 2 more answers