The `qty`

function makes it easy to keep track of different quantities in chemical calculations. Metric prefixes are fully supported, i.e. any unit can be combined with standard metric_scaling scaling (mL, nmol, kg, etc.). Some quantities can also be used in common arithmetic operations.

`qty(x = double(), unit, scale_to_best_metric = TRUE)`

- x
the numeric value of the quantity, can be a single value or a vector

- unit
the unit of the quantity

- scale_to_best_metric
whether to automatically scale to the best metric prefix

The following types of quantities are supported.

*amount (N)*: base unit `mol`

but also understands `mole`

, all metric prefixes allowed

*mass (m)*: base unit `g`

, all metric prefixes allowed

*molecular weight (MW)*: base unit `g/mol`

, all metric prefixes allowed in the numerator

*molarity concentration (C)*: base unit `M`

but also understands `mol/L`

, all metric prefixes allowed in the numerator

*mass concentration (C)*: base unit `g/L`

but also understands `g/l`

, all metric prefixes allowed in the numerator. This is technically a density and sometimes referred to as such in the microbial kitchen documentation.

*volume (V)*: base unit `L`

but also understands `l`

, all metric prefixes allowed

*pressure (P)*: base unit `bar`

but also understands `Pa`

, all metric prefixes allowed, the common non-metric units `atm`

, `psi`

, `Torr`

, `mTorr`

, and `% SP`

(% at standard pressure = % of 1 bar) are also supported and will be automatically converted to `bar`

.

*gas solubility (S)*: base unit `M/bar`

, all metric prefixes allowed in the numerator, the common non-metric unit `M/atm`

is also supported and will be automatically converted to `M/bar`

. This quantity is used for capturing Henry's law constants.

*temperature (T)*: base unit `K`

but also understands `C`

and `F`

and converts them to Kelvin

`qty()`

: generate a quantity object

Other quantity functions:
`check_quantities`

,
`make_qty_units_explicit()`

,
`metric_scaling`

,
`quantity_data`

,
`quantity_units`

```
qty(0.045, "mmol/L")
#> <mk_molarity_concentration[1]>
#> [1] 45
qty(200, "mbar")
#> <mk_pressure[1]>
#> [1] 200
qty(6, "psi")
#> <mk_pressure[1]>
#> [1] 413.6855
qty(30, "C")
#> <mk_temperature[1]>
#> [1] 303.15
qty(100, "K")
#> <mk_temperature[1]>
#> [1] 100
qty(5, "mg/L")
#> <mk_mass_concentration[1]>
#> [1] 5
qty(1, "mM/bar")
#> <mk_gas_solubility[1]>
#> [1] 1
qty(257, "g/mol")
#> <mk_molecular_weight[1]>
#> [1] 257
```