What are the names of the compound (with roman numeral)? Na2SO4

Gennadij [26K]

46.16% of sugar is oxygen

5 0

3 years ago

When 45 g of an alloy, at 25°C, are dropped into 100.0g of water, the alloy absorbs 956J of heat. If the temperature of the allo

Novosadov [1.4K]

You can use this formula to help:

$c = \frac{q}{m \: \times \: change \: in \: t}$

Where:

C = specific heat

q = heat

m = mass

t = temperature

What we know:

C = unknown

q = 956 J

m = 45 g

change in t = 12°C because 37°C - 25°C = 12°C

Plug known values into the formula:

C = 956 J / (45 g) (12°C) and we are left with a specific heat of 1.77J/g°C

Now, convert Joules to calories and then you get:

Answer: A. 0.423 cal/g°C

7 0

3 years ago

Read 2 more answers

An instant cold pack purchased in a pharmacy contains a packet of solid ammonium nitrate surrounded by a pouch of water. When th

gavmur [86]

Answer:

c

letra c certeza confia

8 0

3 years ago

If the half life of a radioactive isotope is 1 day, then how much of the original isotope remains at the end of two days?

ikadub [295]

$\huge{\color{magenta}{\fcolorbox{magenta}{black}{\huge{\color{white}{\fcolorbox{aqua}{black}{✿ᴀɴsᴡᴇʀ✿}}}}}}$

25%

Explanation:

In a half life of a radioactive isotope is 1 day,it means it loses its half mass each day

We a formula for N half life

$\sf { \frac{1}{2} }^{n}$

where n is the number of days

Here the isotope is kept for 2 days

so it's left over mass will be

$\sf { (\frac{1}{2}) }^{2} \\ \\ \\ \frac{1}{2} \times \frac{1}{2} \\ \\ \sf \frac{1}{4}$

It's left over mass 1/4th of the original mass

Now, we need to find it's percentage by multiplying with 100

$\sf \frac{1}{4} \times 100 \%\\ \\ \sf \cancel\frac{100}{4} \% \\ \\ \sf 25\%$

So 25% mass will be left after 2 day of half life radioactive isotope.

8 0

2 years ago

Read 2 more answers

An element's most stable ion forms an ionic compound with bromine, having the formula XBr. If the ion of element X has a mass nu

earnstyle [38]

Answer:

The element is Rubidium . The ion only loss one electron to make the electron 36 . But the proton number(atomic number) is 37. The chemical compound should RbBr

X = Rubidium(Rb)

Explanation:

The ion of element X has a mass number of 85 and electron of 36. An elements is charge if it either loss or receive electron. Base on the charge the ion has loss electron. Bromine usually possess a negatively charge ion. That makes the X electron a positively charge ion.

proton number = Atomic number

Proton number = electron number when not charged

Mass number = proton number + neutron number

Proton is usually same number with the electron to make the element neutral. But when the atom is charge the atom usually loss or gain electron.

In this case, the atom X loss one electron thereby reducing the electron number to 36 . Recall, the electron is equal to proton only if the atom is uncharged. This means the proton number should be 37 as one electron was loss.

Element with proton number(atomic number) of 37 is rubidium. It is an alkali metal that is very reactive.

8 0

4 years ago