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3 years ago

7

Which of the following represents an ion? a 4he b Na 2+ c Ca d Mg

1 answer:

liubo4ka [24]3 years ago

7 0

Na2+(answer B) represent ions.

<h3>Explanation</h3>

This is because it has a charge of 2+. ion is formed when an atom gain or lose electrons. when an atom lose electrons it form ion which is positively charged . On the other hand when atom gain electrons it forms ion of negatively charged. Na2+ has a charge of 2+ since it loses two electrons.

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Bases in solution produce what type of ions?

Natali [406]

Bases produce hydroxide ions, while acids produce hydrogen ions.

Bases have a pH of above 7, and are bitter and slippery.

Answer: <span>c. hydroxide ions</span>

4 0

3 years ago

If a substance has a half life of 58 years and starts with 500 g radioactive, how much remains radioactive after 30 years?

Vilka [71]

Answer:

A = 349 g.

Explanation:

Hello there!

In this case, since the radioactive decay kinetic model is based on the first-order kinetics whose integrated rate law is:

$A=Ao*exp(-kt)$

We can firstly calculate the rate constant given the half-life as shown below:

$k=\frac{ln(2)}{t_{1/2}} =\frac{ln(2)}{58year}=0.012year^{-1}$

Therefore, we can next plug in the rate constant, elapsed time and initial mass of the radioactive to obtain:

$A=500g*exp(-0.012year^{-1} *30year)\\\\A=349g$

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3 years ago

Sodium (Na) and potassium (K) are in the same group in the periodic table. Sodium is in the 11th position. How many valence elec

lapo4ka [179]

It's 1 because there is only one electron on the outer shell.

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3 years ago

Read 2 more answers

Convert the volume to its equivalent in milliliters. 14 μL= ? mL

Diano4ka-milaya [45]

0.014 is the answer

6 0

3 years ago

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A serving of Frosted Flakes cereal contains 235,000 J of energy. Calculate the change in temperature (ΔT) that would occur if th

timama [110]

The change in temperature (ΔT) : 56.14 ° C

<h3>Further explanation</h3>

Given

Cereal energy = 235,000 J

mass of water = 1000 g

Required

the change in temperature (ΔT)

Solution

Heat can be formulated :

Q = m . c . ΔT

c = specific heat for water = 4.186 J / gram ° C

235000 = 1000 . 4.186 . ΔT

$\tt \Delta T=\dfrac{235000}{1000\times 4.186}=56.14^oC$

3 0

3 years ago